nexus-mcp
Nexus MCP is an MCP server that lets AI models invoke AI CLI agents (Codex, Claude Code, OpenCode) as parallel, durable, background tools.
Run single or batch prompts across multiple CLI agents in parallel (batch_prompt / prompt)
Execute research, code review, multi-model comparison, bulk generation, and second-opinion workflows
Start, continue, fork, review, diagnose, status-check, list, cancel, and respond to durable agent jobs (agent_* tools)
Configure persistent preferences: execution mode, model, retries, timeouts, output limits, elicitation, and confirmation prompts
Save and retrieve model tier classifications (quick/standard/thorough)
Auto-retry transient failures with exponential backoff and jitter
Parse JSON-first outputs with temp-file spillover for large responses
Discover 10 prompt templates (code review, debug, research, implement feature, compare models, etc.)
Read runner metadata, config, and preferences via resources like nexus://runners and nexus://config
Support YOLO (auto-approve) and default execution modes, with CLI detection and model selection
Integrates the Gemini CLI as a tool, allowing AI models to perform parallelized research, summarization, and content generation using Google's AI models.
Enables interaction with the OpenCode CLI to query models via Ollama and Ollama Cloud, supporting structured outputs and concurrent multi-model comparisons.
Nexus MCP
An MCP server that enables AI models to invoke AI CLI agents (Codex, Claude Code, OpenCode) as tools. Provides durable workspace-scoped jobs, parallel execution, automatic retries with exponential backoff, JSON-first response parsing, discoverable prompt templates, model tier classification, and persistent preferences through MCP tools, resources, and prompts.
Use Cases
Nexus MCP is useful whenever a task benefits from querying multiple AI agents in parallel rather than sequentially:
Research & summarization — fan out a topic to multiple agents, then synthesize their responses into a single summary with diverse perspectives
Code review — send different files or review angles (security, correctness, style) to separate agents simultaneously
Multi-model comparison — prompt the same question to different models and compare outputs side-by-side for quality or consistency
Bulk content generation — generate multiple test cases, translations, or documentation pages concurrently instead of one at a time
Second-opinion workflows — get independent answers from separate agents before making a decision, reducing single-model bias
Related MCP server: mcp-cli-catalog
Features
Parallel execution —
batch_promptfans out tasks withasyncio.gatherand a configurable semaphore (default concurrency: 3)Durable jobs — start, observe, cancel, and resume normalized agent work through stable job and session identities backed by a private per-user SQLite database
Automatic retries — exponential backoff with full jitter for transient errors (HTTP 429/503)
Output handling — JSON-first parsing, brace-depth fallback for noisy stdout, temp-file spillover for outputs exceeding 50 KB
Execution modes —
default(safe, no auto-approve),yolo(full auto-approve)CLI detection — auto-detects binary path, version, and JSON output capability at startup
Persistent preferences — set defaults for execution mode, model, retries, output limit, and timeout; preferences persist across MCP sessions for the lifetime of the server process
Prompt templates — 10 discoverable workflow scaffolds (code review, debug, research, implement feature, etc.) via
list_prompts/get_prompt; each returns structured messages with expert framing the client can use or ignoreModel tier classification — heuristic-based model classification into quick/standard/thorough tiers; clients can override with sampling or live benchmarks. The
nexus://runnersresource includes tier data per modelTool timeouts — configurable safety timeout (default 15 min) cancels long-running tool calls to prevent the server from blocking indefinitely
Client-visible logging — runner events (retries, output truncation, error recovery) are sent to MCP clients via protocol notifications, not just server stderr
Elicitation — interactive parameter resolution via MCP elicitation; disambiguates missing CLI, offers model selection, confirms YOLO mode, and prompts for elaboration on vague prompts. Auto-detects client support and skips gracefully when unavailable. Suppression flags prevent repeat prompts within a session
Benchmark data sources — server instructions include URLs for Artificial Analysis, OpenRouter, Chatbot Arena, and LLM Stats so clients can fetch live model benchmarks without API keys
Extensible — implement
build_command+parse_output, register inRunnerFactory
Agent | Status |
Codex | Supported |
Claude Code | Supported |
OpenCode | Supported |
Installation
Run with uvx (recommended)
uvx nexus-mcpuvx installs the package in an ephemeral virtual environment and runs it — no cloning required.
To check the installed version:
uvx nexus-mcp --versionTo update to the latest version:
uvx --reinstall nexus-mcpClaude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):
{
"mcpServers": {
"nexus-mcp": {
"command": "uvx",
"args": ["nexus-mcp"],
"env": {
"NEXUS_CODEX_MODEL": "gpt-5.2",
"NEXUS_CODEX_MODELS": "gpt-5.4,gpt-5.4-mini,gpt-5.3-codex,gpt-5.2-codex,gpt-5.2,gpt-5.1-codex-max,gpt-5.1-codex-mini",
"NEXUS_CLAUDE_MODEL": "claude-sonnet-4-6",
"NEXUS_CLAUDE_MODELS": "claude-sonnet-4-6,claude-haiku-4-5-20251001",
"NEXUS_OPENCODE_MODEL": "ollama-cloud/kimi-k2.5",
"NEXUS_OPENCODE_MODELS": "ollama-cloud/glm-5,ollama-cloud/kimi-k2.5,ollama-cloud/qwen3-coder-next,ollama-cloud/minimax-m2.5,ollama/gemini-3-flash-preview"
}
}
}
}Cursor (.cursor/mcp.json in your project or ~/.cursor/mcp.json globally):
{
"mcpServers": {
"nexus-mcp": {
"command": "uvx",
"args": ["nexus-mcp"],
"env": {
"NEXUS_CODEX_MODEL": "gpt-5.2",
"NEXUS_CODEX_MODELS": "gpt-5.4,gpt-5.4-mini,gpt-5.3-codex,gpt-5.2-codex,gpt-5.2,gpt-5.1-codex-max,gpt-5.1-codex-mini",
"NEXUS_CLAUDE_MODEL": "claude-sonnet-4-6",
"NEXUS_CLAUDE_MODELS": "claude-sonnet-4-6,claude-haiku-4-5-20251001",
"NEXUS_OPENCODE_MODEL": "ollama-cloud/kimi-k2.5",
"NEXUS_OPENCODE_MODELS": "ollama-cloud/glm-5,ollama-cloud/kimi-k2.5,ollama-cloud/qwen3-coder-next,ollama-cloud/minimax-m2.5,ollama/gemini-3-flash-preview"
}
}
}
}Claude Code (CLI):
claude mcp add nexus-mcp \
-e NEXUS_CODEX_MODEL=gpt-5.2 \
-e NEXUS_CODEX_MODELS=gpt-5.4,gpt-5.4-mini,gpt-5.3-codex,gpt-5.2-codex,gpt-5.2,gpt-5.1-codex-max,gpt-5.1-codex-mini \
-e NEXUS_CLAUDE_MODEL=claude-sonnet-4-6 \
-e NEXUS_CLAUDE_MODELS=claude-sonnet-4-6,claude-haiku-4-5-20251001 \
-e NEXUS_OPENCODE_MODEL=ollama-cloud/kimi-k2.5 \
-e NEXUS_OPENCODE_MODELS=ollama-cloud/glm-5,ollama-cloud/kimi-k2.5,ollama-cloud/qwen3-coder-next,ollama-cloud/minimax-m2.5,ollama/gemini-3-flash-preview \
-- uvx nexus-mcpGeneric stdio config (any MCP-compatible client):
{
"command": "uvx",
"args": ["nexus-mcp"],
"transport": "stdio",
"env": {
"NEXUS_CODEX_MODEL": "gpt-5.2",
"NEXUS_CLAUDE_MODEL": "claude-sonnet-4-6",
"NEXUS_OPENCODE_MODEL": "ollama-cloud/kimi-k2.5"
}
}All env keys are optional — see Configuration for the full list.
Prerequisites:
Python 3.12+ (download)
uv dependency manager (install guide)
curl -LsSf https://astral.sh/uv/install.sh | sh
Optional (for integration tests):
Codex — check with
codex --versionClaude Code — check with
claude --versionOpenCode — check with
opencode --version
Claude Code note: Nexus invokes Claude Code non-interactively via
claude -p. Anthropic saysclaude -pand Agent SDK usage draw from separate monthly Agent SDK credits starting 2026-06-15, while interactive Claude Code usage remains on plan usage limits: https://support.claude.com/en/articles/15036540-use-the-claude-agent-sdk-with-your-claude-plan
Note: Integration tests are optional. Unit tests run without CLI dependencies via subprocess mocking.
# 1. Clone the repository
git clone <repository-url>
cd nexus-mcp
# 2. Install dependencies
uv sync
# 3. Install pre-commit hooks (runs linting/formatting on commit)
uv run pre-commit install
# 4. Verify installation
uv run pytest # Run tests
uv run mypy src/nexus_mcp # Type checking
uv run ruff check . # Linting
# 5. Run the MCP server
uv run python -m nexus_mcp⚠️ Experimental — This integration has not been validated end-to-end by the maintainer. Expect rough edges in setup and auth. Feedback and bug reports are welcome.
Run an isolated OpenCode server for HTTP-based agent execution alongside the CLI runner. Nexus always lists its OpenCode tools and resources; calls return an explicit configuration error until the server password is set, and request errors while the server is unavailable.
Quick start:
Copy
.env.exampleto.envand setPROJECT_DIRto your project path:cp .env.example .env # Edit .env: set PROJECT_DIR=/path/to/your/projectStart the server:
docker compose up -dAuthenticate with your provider:
docker exec -it opencode-server opencode auth loginVerify the server is healthy:
curl -u opencode:nexus http://localhost:4096/global/health
The server binds to 127.0.0.1 (localhost only) by default for security. See docs/opencode-server-setup.md for the full guide including remote access, multi-project setup, and network security.
Usage
Once nexus-mcp is configured in your MCP client, your AI assistant automatically sees its tools.
The reliable trigger is explicitly asking for output from an external AI agent (e.g. Codex, Claude Code, OpenCode).
Generic "do this in parallel" prompts may be handled by the host AI's own capabilities instead.
The cli parameter is optional — if omitted and the client supports MCP elicitation, the server will
ask which runner to use. The server provides runner metadata (names, models, availability,
execution modes) in its connection instructions — no discovery call needed. The cli parameter
includes a JSON schema enum listing valid runner names.
Fan out a research question (batch_prompt)
You say: "Get perspectives from Codex, Claude Code, and OpenCode on transformer architectures."
{
"tasks": [
{ "cli": "codex", "prompt": "Summarize the key findings of the Attention Is All You Need paper", "label": "codex-summary" },
{ "cli": "claude", "prompt": "What are the main limitations of transformer architectures?", "label": "claude-limitations" },
{ "cli": "opencode", "prompt": "List 3 real-world applications of transformers beyond NLP", "label": "opencode-applications" }
]
}Code review from multiple angles (batch_prompt)
You say: "Have Codex, Claude Code, and OpenCode each review this diff in parallel."
{
"tasks": [
{ "cli": "codex", "prompt": "Review this diff for security vulnerabilities:\n\n<paste diff>", "label": "codex-security-review" },
{ "cli": "claude", "prompt": "Review this diff for correctness and edge cases:\n\n<paste diff>", "label": "claude-correctness-review" },
{ "cli": "opencode", "prompt": "Review this diff for style and maintainability:\n\n<paste diff>", "label": "opencode-review" }
]
}Single-agent prompt
You say: "Ask Codex to explain the difference between TCP and UDP."
{ "cli": "codex", "prompt": "Explain the difference between TCP and UDP in simple terms", "model": "gpt-5.2" }Elicitation (server picks the runner)
You say: "Explain the CAP theorem using one of the available agents."
{ "prompt": "Explain the CAP theorem in simple terms" }If the client supports MCP elicitation, the server asks which runner to use. Pass "elicit": false to skip.
Persistent preferences
You say: "Use YOLO mode with Codex from now on."
{ "execution_mode": "yolo", "model": "gpt-5.2", "max_retries": 5 }Subsequent calls inherit these settings. Preferences persist across MCP sessions for the lifetime of the server process, until explicitly cleared.
Fallback chain: explicit parameter → saved preference → per-runner env → global env → hardcoded default.
MCP Tools
Nexus exposes a durable agent_* surface and the original compatibility prompt surface. Every
durable tool requires an explicit workspace selector containing exactly one of an existing
workspace_id or a filesystem path; Nexus never infers a durable workspace from the server's
current directory. A path is resolved to one canonical workspace identity before admission.
Execution-starting durable tools return a JobHandle immediately. Clients use the observation and
control tools to follow the normalized job independently of an MCP request lifetime.
Tool | Description |
| Create a durable session and queue its first turn |
| Queue another turn on an existing session |
| Create a child session when the backend supports forking |
| Queue a typed review operation on an existing session |
| Queue a sessionless backend diagnostic job |
| Read the current normalized status of one job |
| Read the pending or terminal typed result of one job |
| Page through authorized jobs in one workspace |
| List backend capabilities and current availability for one workspace |
| Request idempotent cancellation of a queued or active job |
| Resolve a pending approval, permission, question, or form input |
The compatibility prompt and batch_prompt tools retain their background-task behavior. They
return FastMCP task IDs so clients can poll without holding a long-running MCP request open.
Per-call concurrency defaults to 3. The shared process runtime starts with 3 workers and grows to
a high-water maximum of 8; one call whose effective demand exceeds 8 is rejected explicitly,
while concurrent calls share the process ceiling and may queue.
Tool | Task? | Description |
| Yes | Fan out prompts to multiple runners in parallel; returns |
| Yes | Single-runner convenience wrapper; routes to |
| No | Set or selectively clear persistent defaults for execution mode, model, retries, timeouts, elicitation, and trigger suppression |
| No | Retrieve current preferences |
| No | Reset all preferences |
| No | Save model tier classifications (client sends sampling/benchmark results; server persists) |
| No | Retrieve saved model tier classifications |
batch_prompt
Parameter | Required | Default | Description |
| Yes | — | List of task objects (see below) |
| No |
| Max parallel agent invocations for this call; effective demand above the process worker maximum of 8 is rejected |
| No | pref or | Enable/disable interactive elicitation for this call |
Task object fields:
Field | Required | Default | Description |
| No | — | Runner name (e.g. |
| Yes | — | Prompt text |
| No | auto | Display label for results |
| No |
| Optional context metadata dict |
| No | pref or |
|
| No | pref or CLI default | Model name override |
| No | pref or env default | Max retry attempts for transient errors |
| No | pref or env default | Max output bytes |
| No | pref or env default | Subprocess timeout in seconds |
| No | pref or env default | Base delay for exponential backoff |
| No | pref or env default | Max delay cap for backoff |
Note:
elicitis a batch-level parameter. When enabled, the server runs a single upfront elicitation pass across all tasks rather than prompting per-task.
prompt
Same parameters as a single task object in batch_prompt, plus elicit (batch-level in batch_prompt, per-call here).
set_preferences
Parameter | Required | Default | Description |
| No | — |
|
| No | — | Model name (e.g. |
| No | — | Max total attempts (≥1; 1 = no retries) |
| No | — | Max output bytes (≥1) |
| No | — | Subprocess timeout seconds (≥1) |
| No | — | Backoff base delay seconds (≥0) |
| No | — | Backoff max delay seconds (≥0) |
| No |
| Enable/disable elicitation |
| No |
| Prompt before YOLO mode (auto-suppressed after first accept) |
| No |
| Prompt on very short prompts |
| No |
| Prompt when max_retries > 5 |
| No |
| Prompt when batch > 5 tasks |
| No |
| Clear any field individually (e.g. |
get_preferences / clear_preferences
get_preferences — no parameters, returns all fields (null when unset).
clear_preferences — no parameters, resets all to null. Does not clear model tiers.
set_model_tiers
Parameter | Required | Default | Description |
| Yes | — | Dict mapping model names to tiers ( |
Persists tier classifications. Clients typically call once via sampling or benchmark fetch.
get_model_tiers
No parameters. Returns saved tiers as dict[str, str], or {} if none saved.
Managing Preferences
Operation | Tool | Notes |
Set fields |
| Persists across sessions |
Read values |
|
|
Clear all |
| Does not clear model tiers |
Clear one field |
| Others preserved |
Suppress elicitation |
| YOLO/batch/retry auto-suppress after accept |
Re-enable prompt |
| Resets to default |
Save/read tiers |
| Persists across sessions |
Durable Job Architecture
The framework-independent core separates normalized domain contracts from concrete backends,
storage, and the MCP transport. A job is one admitted operation and owns its retry attempts,
events, controls, and terminal result. A session is a durable conversation identity bound to one
workspace and backend; agent_start creates it, agent_continue reuses it, and agent_fork
creates a child when supported. Diagnostic jobs may be sessionless. A session and a job are not MCP
client sessions or FastMCP background-task IDs.
Jobs and sessions use private | workspace access policies:
private(the default) is visible only to the owning principal.workspaceis visible to the owner and to callers explicitly authorized for that same workspace. It never grants cross-workspace access. For the local MCP adapter, the operating-system user is the principal and the private database permissions form the trust boundary.
The SQLite database contains sensitive prompts, normalized events, provider references, and
results. Set NEXUS_DB_PATH to override its location. Otherwise Nexus uses these per-user paths:
macOS:
~/Library/Application Support/nexus-mcp/nexus.sqlite3Windows:
%LOCALAPPDATA%\nexus-mcp\nexus.sqlite3(falling back to~/AppData/Local/nexus-mcp/nexus.sqlite3)Linux and other Unix platforms:
${XDG_DATA_HOME:-~/.local/share}/nexus-mcp/nexus.sqlite3
On POSIX systems Nexus removes group and other access from the database directory and SQLite files. Normalized job, session, event, and result records are retained indefinitely by default; Nexus does not schedule automatic pruning. Applying retention cutoffs is an explicit store operation, and no public MCP pruning tool is currently exposed.
Codex, Claude Code, and OpenCode execution currently passes through the temporary
LegacyRunnerBackend bridge while native backends are developed. The bridge supports normalized
turns only: it does not provide backend cancellation, graceful interruption, session forking, or
safe reconciliation after an interrupted attempt. These are legacy-backend limitations, not core
job-model promises; clients should inspect agent_backends capabilities before selecting an
operation.
MCP Prompts
Nexus MCP provides 10 discoverable prompt templates that clients can browse via list_prompts() and render via get_prompt(name, args). Each prompt returns structured messages with expert framing — the client decides how (or whether) to use them.
Design principle: Server informs, client decides. Prompts provide the scaffold (role, structure, methodology); the client decides runner, model, depth, and orchestration. Prompts are completely optional — existing prompt/batch_prompt tools work exactly as before.
Prompt | Tags | Parameters | Purpose |
| analysis |
| Structured code review with findings by severity |
| analysis |
| Systematic diagnosis: reproduce, isolate, root cause, fix |
| analysis |
| Fast assessment: what's wrong, severity, next step |
| analysis |
| Structured research with source citations |
| analysis |
| Independent review of another AI's output |
| generation |
| Feature implementation with quality checklist |
| generation |
| Behavior-preserving restructuring |
| generation |
| Expand template across variable sets |
| testing |
| Test generation with configurable coverage approach |
| comparison |
| Multi-runner comparison framework |
# 1. Client discovers available prompts
list_prompts() → sees "code_review", "debug", "compare_models", etc.
# 2. Client renders a prompt with arguments
get_prompt("code_review", {file: "src/auth.py", instructions: "security vulnerabilities"})
# 3. Server returns structured messages
→ PromptResult(
messages=[
Message("You are a senior code reviewer...", role="assistant"),
Message("Review the file `src/auth.py`...\nFocus: security vulnerabilities\n...", role="user"),
],
description="Code review of src/auth.py"
)
# 4. Client feeds messages into prompt/batch_prompt with chosen runner+model
prompt(cli="claude", prompt=<rendered messages>)MCP Resources
Read-only data endpoints that clients query for runner metadata, configuration, and preferences.
Resource URI | Description |
| All registered CLI runners with models (enriched with tier data), modes, availability |
| Single runner details by name (URI template) |
| Resolved operational config defaults (timeouts, retries, output limits) |
| Current preferences with config fallback |
Models in nexus://runners include tier data: {"name": "gpt-5.4-mini", "tier": "quick"}. Tiers are quick (fast/cheap), standard (balanced), or thorough (max quality). Models with only heuristic tiers appear in unclassified_models — calling set_model_tiers moves them out.
Before set_model_tiers — all tiers are heuristic guesses, all models are unclassified:
{
"models": [
{"name": "gpt-5.1-codex-max", "tier": "thorough"},
{"name": "gpt-5.4-mini", "tier": "quick"},
{"name": "claude-sonnet-4-6", "tier": "standard"}
],
"unclassified_models": ["gpt-5.1-codex-max", "gpt-5.4-mini", "claude-sonnet-4-6"]
}After set_model_tiers — saved tiers replace heuristics, classified models leave the list:
{
"models": [
{"name": "gpt-5.1-codex-max", "tier": "thorough"},
{"name": "gpt-5.4-mini", "tier": "quick"},
{"name": "claude-sonnet-4-6", "tier": "standard"}
],
"unclassified_models": []
}Global Environment Variables
Variable | Default | Description |
| Platform per-user data directory | Durable SQLite job database; contains sensitive prompts and results |
|
| Max output size in bytes before temp-file spillover |
|
| Subprocess timeout in seconds (10 minutes) |
|
| Tool-level timeout in seconds (15 minutes); set to |
|
| Max attempts including the first (set to 1 to disable retries) |
|
| Base seconds for exponential backoff |
|
| Maximum seconds to wait between retries |
|
| Timeout in seconds for CLI binary version detection at startup |
|
| Global execution mode ( |
Per-Runner Environment Variables
Pattern: NEXUS_{AGENT}_{KEY} (agent name uppercased). Per-runner values override global values.
Valid {AGENT} values: CLAUDE, CODEX, OPENCODE, OPENCODE_SERVER
Variable pattern | Example | Description |
|
| Default model for this runner |
|
| Comma-separated model list (surfaced in server instructions) |
|
| Subprocess timeout override |
|
| Output limit override |
|
| Max retry attempts override |
|
| Backoff base delay override |
|
| Backoff max delay override |
|
| Execution mode override |
Invalid per-runner values are silently ignored (the global or hardcoded default is used instead).
Testing
This project follows Test-Driven Development (TDD) with strict Red→Green→Refactor cycles.
# Run all tests
uv run pytest
# Run with coverage report
uv run pytest --cov=nexus_mcp --cov-report=term-missing
# Run specific test types
uv run pytest -m integration # Integration tests (requires CLIs)
uv run pytest -m "not integration" # Unit tests only
uv run pytest -m "not slow" # Skip slow tests
# Run specific test file
uv run pytest tests/unit/runners/test_codex.pyTest markers:
@pytest.mark.integration— requires real CLI installations@pytest.mark.slow— tests taking >1 second
Code Quality
All quality checks run automatically via pre-commit hooks. Run manually:
# Lint and format
uv run ruff check . # Check for issues
uv run ruff check --fix . # Auto-fix issues
uv run ruff format . # Format code
# Type checking (strict mode)
uv run mypy src/nexus_mcp
# Run all pre-commit hooks manually
uv run pre-commit run --all-filesAdding Dependencies
uv add <package> # Production dependency
uv add --dev <package> # Development dependency
uv sync # Sync environment after changesTool Configuration
Ruff: line length 100, 17 rule sets (E/F/I/W + UP/FA/B/C4/SIM/RET/ICN/TID/TC/ISC/PTH/TD/NPY) —
pyproject.toml → [tool.ruff]Mypy: strict mode, all type annotations required —
pyproject.toml → [tool.mypy]Pytest:
asyncio_mode = "auto", no@pytest.mark.asyncioneeded —pyproject.toml → [tool.pytest.ini_options]Pre-commit: ruff-check, ruff-format, mypy, trailing-whitespace, end-of-file-fixer —
.pre-commit-config.yaml
Python 3.12+ Syntax
typekeyword for type aliases:type AgentName = strUnion syntax:
str | None(notOptional[str])matchstatements for complex conditionalsNO
from __future__ import annotations
Project Structure
nexus-mcp/
├── src/nexus_mcp/
│ ├── __main__.py # Entry point
│ ├── core/ # Framework- and provider-independent domain contracts
│ ├── backends/ # Typed backend protocols and runtime registry
│ ├── jobs/ # Job service, worker, SQLite store, and migrations
│ ├── legacy/ # Temporary adapter over existing CLI runners
│ ├── mcp/ # FastMCP transport adapter
│ │ ├── server.py # Server, compatibility tools, and registration
│ │ ├── job_tools.py # Typed durable agent_* tools
│ │ ├── runtime.py # MCP lifespan ownership for job runtime services
│ │ └── prompts/ # Discoverable prompt templates
│ ├── server.py # Compatibility re-export for the MCP server
│ ├── types.py # Compatibility request and response models
│ ├── exceptions.py # Exception hierarchy
│ ├── config.py # Legacy environment configuration
│ ├── process.py # Legacy subprocess wrapper
│ ├── parser.py # Legacy JSON-to-text output parsing
│ ├── cli_detector.py # CLI binary detection and version checks
│ └── runners/
│ ├── base.py # Legacy runner protocol and template method
│ ├── factory.py # RunnerFactory
│ ├── claude.py # ClaudeRunner
│ ├── codex.py # CodexRunner
│ ├── opencode.py # OpenCodeRunner
│ └── opencode_server.py # OpenCode server runner
├── tests/
│ ├── unit/ # Fast, mocked tests
│ │ └── prompts/ # Prompt template tests
│ ├── e2e/ # End-to-end MCP protocol tests
│ ├── integration/ # Real CLI tests
│ └── fixtures.py # Shared test utilities
├── .github/
│ └── workflows/ # CI, security, dependabot
├── pyproject.toml # Dependencies + tool config
└── .pre-commit-config.yaml # Git hooks configurationReleases
Stable releases are cut by running the Tag Release workflow from the Actions
tab and choosing a bump (auto infers it from Conventional Commits since the
last tag). Pre-releases are tagged manually. See RELEASE.md for
the full maintainer workflow, recovery steps, and notes on server.json
placeholder fields.
License
MIT
Available Tools
20 toolsagent_backendsList Agent BackendsBRead-onlyIdempotent
Return deterministic descriptors with fresh availability for a workspace.
| Name | Required | Description | Default |
|---|---|---|---|
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| items | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety and repeatability profile is covered. The description's 'deterministic descriptors' echoes idempotence, while 'fresh availability' adds some behavioral context about current state, but it does not disclose edge cases or workspace identity requirements.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single, front-loaded sentence with no filler; every word contributes meaning. The description is appropriately short for a simple read-only listing tool with rich structured metadata.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With one required parameter, complete annotations, and an output schema available, the description covers the essential operational context. The main gap is the absence of usage guidance, but the structured metadata compensates enough to make the tool invocable and understandable.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, and the workspace parameter is documented as 'Reference to exactly one durable workspace identity.' The description adds no parameter-level detail, so the baseline score of 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The title clearly names the resource ('Agent Backends') and the description provides a verb ('Return') and scope ('for a workspace'), so the core action is knowable. However, 'deterministic descriptors' is abstract and the description does not explicitly distinguish this from conceptually related siblings like agent_status or agent_list.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance about when to choose this tool over alternatives, no exclusions, and no mention of sibling tools. 'For a workspace' provides minimal context but not a decision rule or boundary for appropriate use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_cancelCancel Agent JobADestructiveIdempotent
Request idempotent cancellation of one authorized durable job.
| Name | Required | Description | Default |
|---|---|---|---|
| job_id | Yes | ||
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | Yes | |
| job_id | Yes | |
| event_committed | Yes | |
| cancel_requested | Yes | |
| completed_immediately | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the operation as destructive and idempotent, and the description echoes 'idempotent' while adding the 'authorized' qualifier. It does not describe what cancellation actually does to the job or what state changes occur, so added transparency beyond annotations is limited.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is one concise sentence with no filler or repetition. It front-loads the key action and object, making it quickly scannable for an agent.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a destructive, idempotent operation with two required parameters including a nested workspace object, the one-sentence description is minimal. The output schema and annotations help, but the description still leaves gaps around authorization, failure behavior, and what cancellation implies for the job's lifecycle.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 50%; workspace has a description but job_id does not. The tool description does not explain either parameter in detail, nor does it connect 'one ... durable job' to job_id or workspace meaning, so it fails to compensate for the low coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific action ('Request idempotent cancellation') and a clear resource ('one authorized durable job'). The verb 'cancel' distinguishes this tool from sibling agent_* tools such as agent_start, agent_status, and agent_continue.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The intended use is implied: cancel a durable job. However, the description does not explicitly say when to use this tool versus alternatives like agent_fork or agent_continue, and it does not mention prerequisites or conditions for cancellation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_continueContinue Agent SessionBDestructive
Queue a durable turn against an existing authorized session.
| Name | Required | Description | Default |
|---|---|---|---|
| config | No | ||
| prompt | Yes | ||
| context | No | ||
| file_refs | No | ||
| workspace | Yes | Reference to exactly one durable workspace identity. | |
| session_id | Yes | ||
| idempotency_key | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | No | |
| job_id | Yes | |
| operation | Yes | |
| session_id | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, the description adds useful behavioral context: the turn is 'queued' (asynchronous/non-blocking) and 'durable' (persistent), and the session must be 'authorized' beforehand. It does not elaborate on the destructive behavior implied by destructiveHint=true, but the annotation already covers that signal, so the description adds meaningful context without contradicting the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single front-loaded sentence with no filler or repetition. Every word contributes meaning: the action is 'Queue,' the target is a 'durable turn,' and the precondition is an 'existing authorized session.'
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has 7 parameters, nested objects, an output schema, and several closely related siblings, this one-sentence description is not complete enough for reliable invocation. It omits guidance on configuration, file references, idempotency, and context, and does not clarify how this differs from agent_respond or batch_prompt.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 14%, so the description needed to compensate by explaining key parameters, but it only hints at session_id via 'existing authorized session.' It says nothing about workspace, prompt, config, context, file_refs, or idempotency_key, leaving the agent to infer their roles from the bare schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a specific verb ('Queue') and resource ('a durable turn against an existing authorized session'), which clearly communicates that this tool continues an already-running agent session rather than starting a new one. It distinguishes from siblings like agent_start and agent_fork, though it does not name them and 'durable turn' is somewhat jargon-heavy.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'existing authorized session' implies the tool should be used when a session already exists and is authorized, which provides some usage context. However, it gives no explicit guidance about when to prefer this over agent_respond, agent_fork, batch_prompt, or prompt, and lists no alternatives or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_diagnoseDiagnose Agent BackendDDestructive
Queue backend diagnostics without conditionally hiding the tool.
| Name | Required | Description | Default |
|---|---|---|---|
| config | No | ||
| backend | Yes | ||
| workspace | Yes | Reference to exactly one durable workspace identity. | |
| idempotency_key | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | No | |
| job_id | Yes | |
| operation | Yes | |
| session_id | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations state destructiveHint=true, readOnlyHint=false, and idempotentHint=false, indicating a mutating, non-idempotent operation. The description adds the word 'Queue', implying the diagnostic is submitted asynchronously, but it does not disclose what side effects the diagnostics have (e.g., does it modify backend state, send telemetry, or run commands?). It also does not clarify the meaning of 'without conditionally hiding the tool' in behavioral terms. No contradiction with annotations, but the description adds minimal behavioral context beyond what annotations already cover.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single short sentence with no filler, so it is structurally concise. However, it is under-specified to the point of being unhelpful. The phrase 'without conditionally hiding the tool' appears to be an instruction about tool visibility rather than functionality, wasting space. A useful description would need more detail to meet the minimum viable standard.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complex schema (nested config with 7 subfields, workspace object, idempotency_key) and its destructive, asynchronous nature, the description is far from complete. It does not explain what 'backend diagnostics' are, what the tool returns (output schema exists but is not referenced), or any required setup. Sibling tools like agent_status and agent_backends likely have overlapping functions, and without context the agent cannot reliably choose this tool. The description leaves too many unknowns.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description provides zero information about the parameters (backend, workspace, config, idempotency_key). While the schema includes descriptions for some fields (config and workspace), schema description coverage is only 25%, meaning most parameters lack explanation. The description does not compensate for this gap, leaving agents to guess the purpose and format of the config object and idempotency key.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description mentions 'Queue backend diagnostics', which gives a verb and a resource, indicating the tool queues diagnostics for the backend. However, it does not elaborate on what 'diagnostics' entails, whether it runs tests, collects logs, or checks health. It also does not distinguish it from sibling tools like agent_status or agent_review, which might also involve diagnostic checks. The phrase 'without conditionally hiding the tool' is confusing and does not clarify the tool's purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given on when to use this tool versus alternatives. The description does not mention any prerequisites, conditions, or scenarios that call for diagnosing a backend. There is no mention of alternatives or exclusions, leaving the agent without direction on selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_forkFork Agent SessionBDestructive
Fork an existing session when its backend advertises that capability.
| Name | Required | Description | Default |
|---|---|---|---|
| config | No | ||
| prompt | No | ||
| context | No | ||
| file_refs | No | ||
| workspace | Yes | Reference to exactly one durable workspace identity. | |
| session_id | Yes | ||
| idempotency_key | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | No | |
| job_id | Yes | |
| operation | Yes | |
| session_id | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the operation as destructive and not idempotent; the description adds the backend-capability prerequisite, which is genuine behavioral context. It does not go deeper into what forking does to the original session, whether config is copied, or what makes it destructive, but the annotation coverage lowers the burden somewhat.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single front-loaded sentence with no wasted words, and the key scoping detail ('existing session', 'backend advertises that capability') comes early. It could carry a bit more operational context, but as a concise statement it is effective.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool has seven parameters, a nested config object, destructive annotations, and no usage guidance in the description. An output schema exists, which covers return shape, but the description leaves important gaps around when to fork versus start/continue, parameter roles, and behavioral consequences.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 14%, and the tool description adds no parameter-level meaning. Most parameters like prompt, context, file_refs, session_id, and idempotency_key are left for the agent to infer from names alone, and the nested config object is only explained inside the schema, not in the tool description.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly identifies the action ('Fork') and the resource ('an existing session'), and adds a meaningful condition ('when its backend advertises that capability'). This distinguishes it from agent_start and agent_continue, though it does not explicitly name those siblings, so it stops short of a top score.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'when its backend advertises that capability' gives a condition for using the tool, which is useful context. However, there is no explicit guidance on when not to use it or which sibling tool should be used instead, so usage routing is left mostly to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_listList Agent JobsARead-onlyIdempotent
List one authorized page of durable jobs for an explicit workspace.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| cursor | No | ||
| states | No | ||
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| items | No | |
| next_cursor | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the operation read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond those annotations by noting that only one page is returned and that jobs are durable. There is no contradiction between the description and the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single front-loaded sentence beginning with the verb 'List', and each phrase adds either scope, resource type, or a pagination constraint. It is concise and easily parsable, with no redundant filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given four parameters, a nested workspace object, and many sibling agent_* tools, the definition is only minimally complete. It conveys pagination only through the word 'page', leaves the states filter to be inferred from the schema enum, and does not differentiate usage from agent_status or agent_result. The presence of an output schema reduces the need to describe return values, but key guidance is still missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 25%, with only the workspace object receiving a description. The tool description alludes to pagination ('one page') and workspace scoping, but does not explain limit, cursor, or states, and therefore does not compensate for the low schema coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb-resource pair ('List ... durable jobs') and adds a mandatory scope ('for an explicit workspace'), making the operation distinct from sibling tools such as agent_start, agent_status, and agent_result. The phrase 'authorized page' is slightly opaque, but the core purpose is unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use the tool: to enumerate durable jobs for an explicit workspace, with only one page returned at a time. It does not name alternatives or provide exclusions, so an agent must infer when agent_status or agent_result would be more appropriate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_respondRespond to Agent InputAIdempotent
Resolve one pending typed provider interaction for a durable job.
| Name | Required | Description | Default |
|---|---|---|---|
| job_id | Yes | ||
| input_id | Yes | ||
| response | Yes | ||
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| job_id | Yes | |
| status | No | |
| input_id | Yes | |
| replayed | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide idempotentHint=true and readOnlyHint=false, so the description does not need to restate mutation safety. It adds some scoping context with 'pending' and 'durable job', but it does not explain side effects, lifecycle changes, or what happens after resolution. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single sentence with no filler or redundant restatement of field names. It front-loads the core action and scope, making it easy to scan. Every word contributes to the meaning.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is complex: four required parameters, a nested oneOf response schema, and a workspace object. The description offers almost no lifecycle context, such as how to discover the pending input_id or what 'provider interaction' means in practice. While an output schema exists, the description still lacks enough context for confident invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 25%, and the description does not compensate. It never explains job_id, input_id, workspace, or how to construct the response field. The schema's oneOf block documents acceptable response shapes, but job_id and input_id remain opaque, and 'typed provider interaction' is too indirect to substitute for real parameter guidance.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Resolve') and clearly defines the resource as 'one pending typed provider interaction for a durable job.' The title 'Respond to Agent Input' reinforces the purpose. This is specific enough to distinguish the tool from siblings like agent_start or agent_continue.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context for when to use the tool: when a pending typed provider interaction for a durable job needs to be resolved. It does not explicitly name alternatives or state when not to use it, so it stops short of a 5, but the intended usage is unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_resultGet Agent Job ResultBRead-onlyIdempotent
Return the pending, succeeded, failed, or cancelled durable result variant.
| Name | Required | Description | Default |
|---|---|---|---|
| job_id | Yes | ||
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds genuine behavioral context beyond those annotations by disclosing that the call can return a 'pending' variant — signaling the job may not be finished yet — as well as terminal states. It does not cover error or not-found behavior, but with the annotation bar lowered, the added variant context earns a 4.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single 12-word sentence with no filler, front-loading the verb and resource immediately. Every word earns its place; brevity here is achieved without redundancy, even though it sacrifices some contextual richness that other dimensions capture.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists (covering return values) and annotations fully cover the safety profile, so the description need not repeat those. However, it leaves the relationship to agent_status unexplained, uses the undefined term 'durable result variant', and gives no hint about how to obtain job_id or handle a pending result — clear gaps for a tool with a required nested workspace object.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 50%: workspace has a schema description, but job_id has none, and the tool description adds nothing about either parameter. job_id is a required, unformatted string whose provenance (e.g., from agent_start) is never explained, and the description does not compensate for this gap. The workspace object is at least partially covered by the schema, but the critical job_id parameter remains semantically undocumented.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb ('Return') and resource (the durable result variant of an agent job) and enumerates the four possible variants (pending, succeeded, failed, cancelled), which helps distinguish it from siblings like agent_status. However, the phrase 'durable result variant' is internal jargon and the description never explicitly says it is fetching the outcome/payload of a job started by agent_start, so it stops short of a 5.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to call this tool versus its natural alternatives among the siblings, particularly agent_status (which presumably reports job state) and agent_list. The description neither states when polling is appropriate, how the 'pending' state should be handled, nor when another tool should be chosen instead. Usage is only weakly implied by the name and title.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_reviewReview With AgentBDestructive
Queue a typed review when the session backend supports its target and delivery.
| Name | Required | Description | Default |
|---|---|---|---|
| config | No | ||
| target | Yes | A bounded, provider-neutral target for a code review. | |
| context | No | ||
| delivery | No | inline | |
| file_refs | No | ||
| workspace | Yes | Reference to exactly one durable workspace identity. | |
| session_id | Yes | ||
| instructions | No | ||
| idempotency_key | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | No | |
| job_id | Yes | |
| operation | Yes | |
| session_id | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds a small behavioral note about queueing and a support condition, but does not elaborate on side effects (e.g., destructive behavior) or delivery mechanics. Annotations already declare destructiveHint: true and readOnlyHint: false, so the description contributes limited extra context beyond what is already structured.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence with no fluff. It clearly states the action and a condition, achieving excellent conciseness and structure.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with nine parameters, nested objects, and an output schema, this one-line description is severely under-specified. It provides no guidance on constructing the workspace, configuring the review, or interpreting the output, making correct invocation highly unlikely.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description does not explain any of the nine parameters. It alludes to 'target and delivery' but provides no semantics for them. With schema description coverage at only 22%, this is a significant gap that the description fails to compensate for.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific action ('Queue a typed review') and a condition ('when the session backend supports its target and delivery'), clearly identifying the tool's core purpose without being a tautology. However, it does not explicitly differentiate from sibling tools like agent_session_review, so it falls short of a 5.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It gives a conditional prerequisite regarding session backend support, which hints at when the tool is appropriate. But it does not name alternatives or specify when to use this tool instead of batch_prompt or agent_session_review, leaving usage guidance only partially developed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_startStart Agent JobBDestructive
Start a durable session turn in an explicitly selected workspace.
| Name | Required | Description | Default |
|---|---|---|---|
| config | No | ||
| prompt | Yes | ||
| backend | Yes | ||
| context | No | ||
| file_refs | No | ||
| workspace | Yes | Reference to exactly one durable workspace identity. | |
| access_policy | No | private | |
| idempotency_key | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| state | No | |
| job_id | Yes | |
| operation | Yes | |
| session_id | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already signal destructiveHint=true, idempotentHint=false, openWorldHint=true, and readOnlHint=false. The description adds that the session is 'durable' and requires an explicit workspace, which is useful context, but it does not explain what resources are created, what side effects may occur, or what 'durable session' entails.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single focused sentence with no filler. It front-loads the action and the most important constraint, making it easy to parse quickly.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
This is a complex tool with 8 parameters, 3 required, and destructive/open-world annotations, yet the description provides almost no workflow context, no explanation of what a 'durable session turn' means, and no guidance relative to sibling tools. The output schema and annotations help, but they do not make up for the missing high-level usage semantics.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With schema description coverage at only 13% and eight parameters, the description needed to compensate by explaining key parameters like backend and prompt. It only reinforces the workspace concept and leaves required fields and config, context, file_refs, access_policy, and idempotency_key unexplained.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a specific action ('Start'), a specific resource ('a durable session turn'), and a scope ('in an explicitly selected workspace'). It clearly distinguishes this from continuation tools like agent_continue and one-shot prompt tools, though it does not name any sibling explicitly.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The phrase 'Start a durable session turn in an explicitly selected workspace' implies this tool is for beginning a new persistent agent run in a chosen workspace, contrasting with continuing or responding to an existing session. However, it gives no explicit when-to-use or when-not-to-use guidance and does not name alternative tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
agent_statusGet Agent Job StatusBRead-onlyIdempotent
Return one authorized durable job status projection.
| Name | Required | Description | Default |
|---|---|---|---|
| job_id | Yes | ||
| workspace | Yes | Reference to exactly one durable workspace identity. |
Output Schema
| Name | Required | Description |
|---|---|---|
| phase | No | |
| state | Yes | |
| job_id | Yes | |
| operation | Yes | |
| backend_id | Yes | |
| created_at | Yes | |
| session_id | No | |
| updated_at | Yes | |
| completed_at | No | |
| workspace_id | Yes | |
| pending_inputs | No | |
| resolved_config | No | |
| cancel_requested | No | |
| latest_event_sequence | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds modest context with 'authorized' and 'durable', implying access requirements and persistence, but does not explain behavioral details like consistency, blocking, or failure modes.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single concise sentence with no filler and it front-loads the action. It loses a point for the jargon-heavy phrase 'status projection', which could be clearer.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With an output schema, strong safety annotations, and only two required parameters, the tool is reasonably simple. However, the description provides no rationale for selecting this tool over status/result siblings and only vaguely hints at authorization, leaving the context minimally complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is only 50%; job_id is undocumented and the description does not explain either parameter. The workspace object has a schema-level description, but the description text adds no parameter semantics, so it does not compensate for the coverage gap.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Return') and identifies a singular resource ('one authorized durable job status projection'), making the core function clear. It also distinguishes from sibling tools by emphasizing 'one' status versus agent_list or agent_result, though the term 'projection' is somewhat vague.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given about when to choose this tool over sibling tools such as agent_list, agent_result, or agent_cancel. The description only states what it returns and leaves all usage-context decisions to the agent.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
batch_promptBatch Prompt CLI AgentsADestructive
Send multiple prompts to CLI runners in parallel (primary tool).
Fans out tasks server-side with asyncio.gather and a semaphore, enabling true parallel runner execution within a single MCP call. Single-task usage is perfectly valid — use prompt for convenience when sending one task.
| Name | Required | Description | Default |
|---|---|---|---|
| tasks | Yes | List of AgentTask objects, each with cli, prompt, and optional fields. | |
| elicit | No | ||
| max_concurrency | No | Max parallel runner invocations for this call (default: 3). The process worker maximum is 8; one call whose effective demand exceeds 8 is rejected. |
Output Schema
| Name | Required | Description |
|---|---|---|
| total | Yes | |
| failed | Yes | |
| results | Yes | |
| succeeded | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (destructiveHint=true), the description adds meaningful behavioral context: it discloses server-side fan-out with asyncio.gather and a semaphore, explaining true parallel execution within a single MCP call. It also notes that single-task usage is valid, which is a non-obvious trait. This adds transparency without contradicting the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is compact and well-structured. The first sentence states the primary purpose, the second provides behavioral context, and the third gives routing guidance. Every sentence contributes essential information with no redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (parallel fan-out, concurrency limits, multiple options), the description covers the core behavior and usage distinction. An output schema exists, so return values are handled. It could mention potential failure modes or concurrency limits, but the max_concurrency parameter description already covers that. Overall, it is sufficiently complete for an agent to call it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema already covers 67% of parameters (tasks and max_concurrency have descriptions). The tool description adds little parameter-level detail; it references parallelism and concurrency but does not elaborate on individual fields. With high schema coverage, the baseline of 3 applies, and the description does not meaningfully raise it.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb and resource: 'Send multiple prompts to CLI runners in parallel.' It explicitly labels itself as the 'primary tool' and distinguishes it from the sibling 'prompt' for single-task convenience, making the tool's role immediately clear.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives explicit usage guidance: it states when to use this tool (multiple prompts, parallel execution) and when to use the alternative (single task: 'use prompt for convenience'). This directly routes the agent to the correct sibling without ambiguity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
clear_preferencesClear Session PreferencesADestructiveIdempotent
Clear all persistent preferences, reverting to per-call defaults.
Returns: Confirmation string.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructiveHint=true and idempotentHint=true. The description adds behavioral context by explaining that it reverts to per-call defaults and returns a confirmation string, clarifying the meaning of 'destructive'.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise (two sentences), front-loaded with the purpose, and includes the return type. Every word is necessary.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has 0 parameters and annotations cover safety traits, the description is complete: it states what it clears, the effect, and the return value. No gaps for invoking correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With 0 parameters and 100% schema coverage (vacuously), the description adds no parameter information beyond the schema. Baseline for 0 params is 4.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb 'Clear' and resource 'persistent preferences', and distinguishes it from siblings like 'set_preferences' by stating it reverts to per-call defaults.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives like 'set_preferences'. It lacks context about prerequisites or appropriate scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
opencode_investigateOpencode InvestigateA
Search project files and return the matching results.
Chains GET /find → GET /file/content for up to max_files results.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | ||
| max_files | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description takes on the burden of revealing behavior. It explicitly discloses the GET /find and GET /file/content call chain and the max_files limit, indicating a read-only operation. It does not discuss rate limits or edge cases, but the core behavior is transparent for a simple search tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two short sentences with no wasted words. The main purpose is front-loaded, and the endpoint chain is presented succinctly in the second sentence.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple with only two parameters and an output schema, so the description does not need to explain return values. It covers the core operation, the endpoint chain, and the max_files behavior adequately, though examples or query format hints would make it complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description is expected to explain parameters. It does clarify that max_files limits the number of results, but query is only implied by the phrase 'Search project files' and not given explicit semantics such as search syntax or scope. This is partial compensation for the low schema coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states that the tool searches project files and returns matching results, which is a specific verb and resource. It does not explicitly differentiate from sibling tools, but the focus on file search is distinct from the agent and configuration siblings listed.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context for when to use the tool: whenever you need to search project files and retrieve matching file contents. It does not mention exclusions or alternatives, but none of the sibling tools appear to perform a similar file-search function.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
opencode_session_reviewOpencode Session ReviewA
Review a session's messages and file changes.
Chains GET /session/{id} → GET /session/{id}/message → GET /session/{id}/diff → GET /session/{id}/todo.
| Name | Required | Description | Default |
|---|---|---|---|
| session_id | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden, and it provides strong transparency by spelling out the ordered chain of GET endpoints: session, message, diff, and todo. This makes the read-only, multi-call nature clear, though auth requirements and failure behavior are not disclosed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no wasted words. The purpose is front-loaded, and the endpoint chain is compactly listed in one line, making the behavioral flow immediately readable.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description captures the full endpoint flow and the single required input, and an output schema exists so return-value documentation is not needed. It could add guidance on when to prefer this over agent_review or agent_diagnose, but as a standalone review action it is reasonably complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description must compensate. The path template 'GET /session/{id}' embeds the single parameter and conveys that session_id is the session path identifier, which is enough despite not specifying format or length.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a concrete operation—'Review a session's messages and file changes'—with a clear resource and outcome. The GET /session/{id} chain reinforces the exact scope, and the session-scoped phrasing distinguishes it from sibling agent_* review/diagnose tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit when-to-use guidance, exclusions, or alternatives are provided. The description only implies this is for reviewing a session, which does not help an agent choose between this and similarly named tools like agent_review or agent_diagnose.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
opencode_set_provider_authOpenCode ConfigurationCIdempotent
Set authentication credentials for a provider.
| Name | Required | Description | Default |
|---|---|---|---|
| credentials | Yes | ||
| provider_id | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate this is a non-read-only, non-destructive, idempotent operation. The description adds no behavioral detail beyond the act of setting credentials, such as whether existing credentials are overwritten, how credentials are stored, or whether any validation occurs.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single, front-loaded sentence with no filler. It is efficient, though it is so brief that it leaves useful operational guidance unstated.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For an auth-setting tool with minimal schema parameter documentation, the description is too thin. It lacks usage boundaries, side-effect disclosure, and parameter detail, leaving an agent without enough context to confidently invoke it correctly among related configuration tools.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The schema has 0% parameter description coverage, so the description must compensate. It relates provider_id and credentials to the overall purpose, but does not explain acceptable credential shapes, required fields, or how provider_id should be specified.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb and target: 'Set authentication credentials for a provider.' This clearly communicates the tool's core purpose and distinguishes it from generic configuration operations. Some ambiguity remains with opencode_update_config, but the credential-specific focus is strong enough.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is given about when to use this tool versus siblings like opencode_update_config, set_preferences, or clear_preferences. There are no preconditions, exclusions, or alternative tool mentions, so an agent must infer usage context from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
opencode_update_configOpenCode ConfigurationCIdempotent
Update OpenCode server configuration.
| Name | Required | Description | Default |
|---|---|---|---|
| config | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate the operation is not read-only, is idempotent, and is non-destructive, so the description adds no extra behavioral context. It does not explain whether the update merges or replaces the existing configuration, whether a restart is needed, or what side effects may occur.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a single short sentence with no fluff. It front-loads the verb and resource, making it easy to parse quickly.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is complex because its only input is an open-ended config object, yet the description provides no detail about what fields or settings can be included. Although an output schema exists and annotations are present, the description still leaves a significant gap for the agent to understand how to construct a valid config and what the tool's effective scope is.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The only parameter, 'config', is an arbitrary object with no property descriptions in the schema and a schema description coverage of 0%. The description merely says 'configuration', which adds minimal semantic value beyond the parameter name. It provides no examples, keys, format, or constraints.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly names the action ('Update') and the resource ('OpenCode server configuration'). It is a meaningful statement rather than a tautology, and 'server configuration' hints at a broader scope than sibling tools like set_model_tiers or set_preferences. However, it doesn't explicitly differentiate itself from those siblings.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is provided about when to use this tool versus alternatives such as opencode_set_provider_auth, set_model_tiers, or set_preferences. An agent reading this alone cannot determine whether to use this tool or a more specific one.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
promptPrompt CLI AgentADestructive
Send a prompt to a CLI runner as a background task.
Returns immediately with a task ID. Client polls for results. This prevents timeouts for long operations (YOLO mode: 2-5 minutes).
| Name | Required | Description | Default |
|---|---|---|---|
| cli | No | CLI runner name (e.g., "codex"). None triggers interactive selection. | |
| model | No | Model name. None triggers interactive selection or uses CLI default. | |
| elicit | No | ||
| prompt | Yes | Prompt text to send to the runner | |
| context | No | Optional context metadata | |
| timeout | No | Subprocess timeout seconds (None inherits session preference or uses env default). | |
| max_retries | No | Max retry attempts for transient errors (None inherits session preference). | |
| output_limit | No | Max output bytes (None inherits session preference or uses env default). | |
| execution_mode | No | 'default' (safe) or 'yolo'. None inherits session preference. | |
| retry_max_delay | No | Backoff ceiling in seconds (None inherits session preference or config). | |
| retry_base_delay | No | Base delay seconds for exponential backoff (None inherits session/config). |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate destructiveHint=true, but the description adds valuable behavioral details: returns immediately with task ID, client polls, prevents timeouts, and specifies YOLO mode duration. This exceeds annotation-only info.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three sentences with no wasted words. Front-loaded with core action, followed by async behavior and benefit. Highly concise and structured.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity (11 parameters, async, destructive), the description covers the key workflow (async polling, timeout). Output schema exists, so return format is covered elsewhere. Missing minor details like polling mechanism, but sufficient.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
With 91% schema coverage, the description adds minimal parameter detail beyond the schema. It mentions YOLO mode and timeout but does not explain individual parameters further. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it sends a prompt to a CLI runner as a background task, returns immediately with a task ID, and prevents timeouts. This distinguishes it from siblings like batch_prompt (batch) and preference tools.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains the async nature and timeout prevention, providing clear context for use. However, it does not explicitly contrast with sibling tools like batch_prompt or state when not to use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
set_model_tiersSet Model TiersAIdempotent
Save model tier classifications.
Client sends sampling/benchmark results; server persists to backing store. Overwrites any previously saved tiers entirely.
| Name | Required | Description | Default |
|---|---|---|---|
| tiers | Yes | Mapping of model name to tier ('quick', 'standard', 'thorough'). |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description explicitly states it overwrites previously saved tiers entirely, adding behavioral context beyond annotations. Annotations already indicate idempotence, but the description clarifies the overwriting behavior. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three efficient sentences: first states purpose, second explains process, third details effect. No wasted words, and critical information is front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple with one parameter, full schema coverage, and an output schema. The description covers the key behavior (overwrite) and is complete for this complexity level, though it omits error handling details.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and the schema already describes the tiers parameter as a mapping to allowed tier values. The description adds no further meaning, so baseline score is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool saves model tier classifications, using a specific verb (Save) and resource (model tier classifications). It distinguishes from sibling tools like prompt and set_preferences, which deal with prompts and preferences.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No explicit guidance on when to use vs. alternatives. The context implies it is for persisting model tiers after sampling/benchmarks, but lacks explicit when-not-to-use or comparison with siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
set_preferencesSet Session PreferencesAIdempotent
Set persistent preferences that apply to subsequent prompt/batch_prompt calls.
Preferences persist across MCP sessions. Call again to update, or use clear_preferences to reset all fields at once.
To clear a single field while keeping others, pass the corresponding clear_* flag: set_preferences(clear_model=True) # clears model, keeps execution_mode
| Name | Required | Description | Default |
|---|---|---|---|
| model | No | Default model name (e.g. 'gpt-5.2'). None retains the current value (use clear_model=True to reset). | |
| elicit | No | ||
| timeout | No | Default subprocess timeout in seconds. None retains the current value (use clear_timeout=True to reset). | |
| clear_model | No | If True, resets model to None regardless of the model argument. | |
| max_retries | No | Default max retry attempts for transient errors. None retains the current value (use clear_max_retries=True to reset). | |
| clear_elicit | No | ||
| confirm_yolo | No | ||
| output_limit | No | Default max output bytes per response. None retains the current value (use clear_output_limit=True to reset). | |
| clear_timeout | No | If True, resets timeout to None regardless of the argument. | |
| execution_mode | No | Default execution mode ('default' or 'yolo'). None retains the current value (use clear_execution_mode=True to reset). | |
| retry_max_delay | No | Default max delay cap seconds for exponential backoff. None retains the current value (use clear_retry_max_delay=True to reset). | |
| retry_base_delay | No | Default base delay seconds for exponential backoff. None retains the current value (use clear_retry_base_delay=True to reset). | |
| clear_max_retries | No | If True, resets max_retries to None regardless of the argument. | |
| clear_confirm_yolo | No | ||
| clear_output_limit | No | If True, resets output_limit to None regardless of the argument. | |
| confirm_large_batch | No | ||
| clear_execution_mode | No | If True, resets execution_mode to None regardless of the execution_mode argument. | |
| confirm_high_retries | No | ||
| confirm_vague_prompt | No | ||
| clear_retry_max_delay | No | If True, resets retry_max_delay to None. | |
| clear_retry_base_delay | No | If True, resets retry_base_delay to None. | |
| clear_confirm_large_batch | No | ||
| clear_confirm_high_retries | No | ||
| clear_confirm_vague_prompt | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate idempotency ('idempotentHint': true) and non-destructiveness. The description adds value by explaining persistence across sessions and the update semantics. No contradictions found.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Well-structured with three concise paragraphs: purpose, persistence, and example usage. No unnecessary words, every sentence adds value.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with 24 parameters (none required) and an output schema, the description covers the key behavioral aspects: persistence, update, clearing, and relation to sibling tools. The output schema handles return values, so no further detail needed.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 58% with descriptions for most fields. The description explains the overall pattern of using 'None' to retain values and 'clear_*' flags to reset, which adds context beyond individual parameter descriptions but does not detail every parameter.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the verb ('Set'), resource ('persistent preferences'), and scope ('apply to subsequent prompt/batch_prompt calls'). It effectively distinguishes from sibling tool 'clear_preferences' by mentioning its specific function.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides explicit guidance on when to use (set preferences for future calls), persistence across sessions, update behavior, and how to clear fields individually using 'clear_*' flags. Also names 'clear_preferences' as alternative for resetting all fields.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
16 tool updates
v1.1.0- Added
agent_backends - Added
agent_cancel - Added
agent_continue - Added
agent_diagnose - Added
agent_fork - Added
agent_list - Added
agent_respond - Added
agent_result - Added
agent_review - Added
agent_start - Added
agent_status - Changed
batch_prompt1 field changed- changed
Input schema / properties / max_concurrency / descriptionPrevious value: -"Max parallel runner invocations (default: 3)."New value: +"Max parallel runner invocations for this call (default: 3). The\nprocess worker maximum is 8; one call whose effective demand exceeds 8 is rejected."
- Added
opencode_investigate - Added
opencode_session_review - Added
opencode_set_provider_auth - Added
opencode_update_config
5 tool updates
v1.0.0- Changed
batch_prompt9 fields changed- added
Input schema / properties / elicitAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / max_concurrency / descriptionAdded value: +"Max parallel runner invocations (default: 3)." - added
Input schema / properties / tasks / descriptionAdded value: +"List of AgentTask objects, each with cli, prompt, and optional fields." - added
Input schema / properties / tasks / items / properties / cli / anyOfAdded value: +[ + { + "minLength": 1, + "type": "string" + }, + { + "type": "null" + } +] - added
Input schema / properties / tasks / items / properties / cli / defaultAdded value: +null - changed
Input schema / properties / tasks / items / properties / cli / enumPrevious value: -[ - "claude", - "codex", - "gemini", - "opencode" -]New value: +[ + "claude", + "codex", + "opencode", + "opencode_server" +] - removed
Input schema / properties / tasks / items / properties / cli / minLengthRemoved value: -1 - removed
Input schema / properties / tasks / items / properties / cli / typeRemoved value: -"string" - changed
Input schema / properties / tasks / items / requiredPrevious value: -[ - "cli", - "prompt" -]New value: +[ + "prompt" +]
- Removed
get_preferences - Changed
prompt16 fields changed- added
Input schema / properties / cli / anyOfAdded value: +[ + { + "type": "string" + }, + { + "type": "null" + } +] - added
Input schema / properties / cli / defaultAdded value: +null - added
Input schema / properties / cli / descriptionAdded value: +"CLI runner name (e.g., \"codex\"). None triggers interactive selection." - changed
Input schema / properties / cli / enumPrevious value: -[ - "claude", - "codex", - "gemini", - "opencode" -]New value: +[ + "claude", + "codex", + "opencode", + "opencode_server" +] - removed
Input schema / properties / cli / typeRemoved value: -"string" - added
Input schema / properties / context / descriptionAdded value: +"Optional context metadata" - added
Input schema / properties / elicitAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / execution_mode / descriptionAdded value: +"'default' (safe) or 'yolo'. None inherits session preference." - added
Input schema / properties / max_retries / descriptionAdded value: +"Max retry attempts for transient errors (None inherits session preference)." - added
Input schema / properties / model / descriptionAdded value: +"Model name. None triggers interactive selection or uses CLI default." - added
Input schema / properties / output_limit / descriptionAdded value: +"Max output bytes (None inherits session preference or uses env default)." - added
Input schema / properties / prompt / descriptionAdded value: +"Prompt text to send to the runner" - added
Input schema / properties / retry_base_delay / descriptionAdded value: +"Base delay seconds for exponential backoff (None inherits session/config)." - added
Input schema / properties / retry_max_delay / descriptionAdded value: +"Backoff ceiling in seconds (None inherits session preference or config)." - added
Input schema / properties / timeout / descriptionAdded value: +"Subprocess timeout seconds (None inherits session preference or uses env default)." - changed
Input schema / requiredPrevious value: -[ - "cli", - "prompt" -]New value: +[ + "prompt" +]
- Added
set_model_tiers - Changed
set_preferences24 fields changed- added
Input schema / properties / clear_confirm_high_retriesAdded value: +{ + "default": false, + "type": "boolean" +} - added
Input schema / properties / clear_confirm_large_batchAdded value: +{ + "default": false, + "type": "boolean" +} - added
Input schema / properties / clear_confirm_vague_promptAdded value: +{ + "default": false, + "type": "boolean" +} - added
Input schema / properties / clear_confirm_yoloAdded value: +{ + "default": false, + "type": "boolean" +} - added
Input schema / properties / clear_elicitAdded value: +{ + "default": false, + "type": "boolean" +} - added
Input schema / properties / clear_execution_mode / descriptionAdded value: +"If True, resets execution_mode to None regardless of the\nexecution_mode argument." - added
Input schema / properties / clear_max_retries / descriptionAdded value: +"If True, resets max_retries to None regardless of the argument." - added
Input schema / properties / clear_model / descriptionAdded value: +"If True, resets model to None regardless of the model argument." - added
Input schema / properties / clear_output_limit / descriptionAdded value: +"If True, resets output_limit to None regardless of the argument." - added
Input schema / properties / clear_retry_base_delay / descriptionAdded value: +"If True, resets retry_base_delay to None." - added
Input schema / properties / clear_retry_max_delay / descriptionAdded value: +"If True, resets retry_max_delay to None." - added
Input schema / properties / clear_timeout / descriptionAdded value: +"If True, resets timeout to None regardless of the argument." - added
Input schema / properties / confirm_high_retriesAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / confirm_large_batchAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / confirm_vague_promptAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / confirm_yoloAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / elicitAdded value: +{ + "anyOf": [ + { + "type": "boolean" + }, + { + "type": "null" + } + ], + "default": null +} - added
Input schema / properties / execution_mode / descriptionAdded value: +"Default execution mode ('default' or 'yolo').\nNone retains the current value (use clear_execution_mode=True to reset)." - added
Input schema / properties / max_retries / descriptionAdded value: +"Default max retry attempts for transient errors.\nNone retains the current value (use clear_max_retries=True to reset)." - added
Input schema / properties / model / descriptionAdded value: +"Default model name (e.g. 'gpt-5.2').\nNone retains the current value (use clear_model=True to reset)." - added
Input schema / properties / output_limit / descriptionAdded value: +"Default max output bytes per response.\nNone retains the current value (use clear_output_limit=True to reset)." - added
Input schema / properties / retry_base_delay / descriptionAdded value: +"Default base delay seconds for exponential backoff.\nNone retains the current value (use clear_retry_base_delay=True to reset)." - added
Input schema / properties / retry_max_delay / descriptionAdded value: +"Default max delay cap seconds for exponential backoff.\nNone retains the current value (use clear_retry_max_delay=True to reset)." - added
Input schema / properties / timeout / descriptionAdded value: +"Default subprocess timeout in seconds.\nNone retains the current value (use clear_timeout=True to reset)."
5 tool updates
v0.8.1- First observed
batch_prompt - First observed
clear_preferences - First observed
get_preferences - First observed
prompt - First observed
set_preferences
TDQS
Scored across 20 tools
Most agent_* tools are clearly distinct lifecycle actions, and the opencode_* tools cover different concerns. The main ambiguity is between agent_status and agent_result, which both appear to return a single durable job's state, and prompt/batch_prompt have overlapping purposes despite the description trying to differentiate them.
All names use snake_case and are grouped by prefixes like agent_ and opencode_, which helps readability. However, there is no consistent verb_noun pattern: prompt and batch_prompt are noun-style, agent_status/agent_result are noun phrases, while agent_start/agent_cancel are verb phrases, and opencode_investigate is a bare verb.
At 20 tools, the server sits in the borderline-heavy range, and the count is somewhat inflated by overlapping pairs like prompt/batch_prompt and agent_status/agent_result. The durable session lifecycle justifies many tools, but the set feels cluttered rather than tightly scoped.
The durable job lifecycle is well covered with start, continue, fork, review, diagnose, cancel, respond, status, result, list, and backends. Minor gaps exist, such as no explicit way to read current preferences or model tiers after setting them, but agents can work around these with the update/clear tools.
Maintenance
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