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What is this?

MCP Light Memory is a lightweight, local-first, persistent memory system for coding agents and MCP clients (Warp, OpenCode, JetBrains AI Assistant / PyCharm, Claude Code, Cursor). It acts as a checkpoint + retrieval layer — it stores the minimum durable state needed to resume complex work across sessions, without keeping the full conversation in the model's context window.

When your agent starts a task, it calls context and gets back relevant past decisions, gotchas, constraints, and hypotheses — ranked, deduplicated, and trust-bounded. When it finishes, it checkpoints the working state. Next session, even after a restart, the memory is there.

Related MCP server: M3 Memory

Why use it?

Problem

How MCP Light Memory solves it

Agents forget everything between sessions

Markdown files persist on disk; the agent retrieves them via BM25 + optional embeddings

Full session history is too large for context

Only relevant memories are retrieved (token-budgeted, MMR-diversified)

Cloud dependency / privacy concerns

100% local, offline, zero network calls, no daemon

Heavy setup / dependencies

Zero required runtime deps (pure Python 3.8+ stdlib); optional sentence-transformers for better semantic retrieval

Prompt injection via stored memory

Every retrieved memory is explicitly trust: untrusted evidence with an injection-warning heuristic (ADR-015)

Multi-project isolation

Router with registry allowlist, write:false hard boundary, per-call subprocess isolation

MCP protocol drift

Dual-era support: modern 2026-07-28 + legacy 2024-11-05…2025-11-25

How it works (mechanisms)

  • Markdown is the source of truth. Every memory is a .md file with YAML frontmatter (id, type, status, tags, sources, links, valid_from, valid_to, supersedes). Human-readable, diffable, durable.

  • SQLite is a rebuildable cache. BM25/FTS5 index + optional embedding vectors + usage tracking. Delete it and everything rebuilds from Markdown.

  • Retrieval: pure-Python BM25 + optional dense embeddings → RRF fusion → MMR diversification → policy boosts (type/status/temporal) → token-budget cut. Adaptive mode: sparse first, dense only if weak.

  • Lifecycle: remember → update → supersede (links both directions, never deletes history) → forget (archives, never deletes) → timeline (temporal view). search --at YYYY-MM-DD for historical queries.

  • Trust boundary: retrieved content is wrapped in === BEGIN/END INTERNAL_RAG MEMORY === with a SECURITY NOTICE header. Structured JSON/MCP carries trust: untrusted + optional security_flags: ["instruction_like_content"].

  • Evidence freshness: each result includes evidence_state (present/missing/unverifiable) for local path-like evidence — derived at retrieval time, never persisted.

  • Multi-project router: one MCP stdio server in front of many projects via a JSON registry. write:false blocks mutating tools before spawning a child. Per-call subprocess isolation (no shared state).

Setup

Prerequisites

  • Python 3.8+ (uses py launcher, python, or python3 — the installer auto-detects the real interpreter and rejects the WindowsApps stub)

  • Git (the target project must be a git repo)

  • Optional: pip install sentence-transformers numpy for better semantic retrieval

The current version is defined by the VERSION file — check it (or run mlm.py --version) instead of hard-coding an expected number.

Quick start

Clone this repo once, then install into any project:

# Windows (PowerShell)
git clone https://github.com/PeterPirog/mcp-light-memory.git ~/mcp-light-memory
python ~/mcp-light-memory/install.py . --client warp
# Linux/macOS
git clone https://github.com/PeterPirog/mcp-light-memory.git ~/mcp-light-memory
python3 ~/mcp-light-memory/install.py . --client warp

The installer:

  • copies skill files + creates INTERNAL_RAG/ + AGENTS.md

  • runs init + checkpoint + validate (so guard is OK immediately)

  • auto-registers the MCP server in the client config when it can do so safely (or reports MANUAL_REQUIRED / prints JetBrains instructions)

  • writes the absolute path to the verified Python interpreter (survives Windows PATH issues)

python .agents\skills\internal-rag\mlm.py --version   # reports the installed version
python .agents\skills\internal-rag\mlm.py status       # expect: INTERNAL_RAG ready
python .agents\skills\internal-rag\mlm.py guard        # expect: GUARD OK

Installation matrix

One installer, four clients, two config scopes. Full guide: docs/INSTALLATION.md.

Client

Project scope

Global scope

Warp (config write automatic; project activation may require approval)

install.py . --client warp

install.py . --client warp --global

OpenCode stable (V1) (automatic for safe JSON config writes)

install.py . --client opencode

install.py . --client opencode --global

OpenCode 2 (V2, beta) (automatic for safe JSON config writes)

install.py . --client opencode2

install.py . --client opencode2 --global

JetBrains AI / PyCharm (manual in IDE UI)

install.py . --client jetbrains

install.py . --client jetbrains --global

  • --global changes the scope of the CLIENT CONFIG (~/.warp/.mcp.json vs {repo}/.warp/.mcp.json, ~/.config/opencode/opencode.json vs project opencode.json). The server still points at the target project you installed into.

  • Need one global MCP endpoint for many repositories? Use the multi-project router — docs/MCP-MULTI-PROJECT.md.

  • JetBrains/PyCharm is assisted, not fully automatic: the installer prepares the JSON + Working Directory; you add the server in Settings → Tools → AI Assistant → MCP and choose Server level = Project or Global.

  • Manual setup (no installer) per client: docs/INSTALLATION.md + client pages (Warp · OpenCode).

Zero-shot: copy-paste prompts for Warp and OpenCode

You can paste one of these directly into the client agent. Replace C:\Projects\App with the real target repository path.

Warp — install for one project:

Install and configure MCP Light Memory (mcp-light-memory) as an MCP server for project C:\Projects\App in Warp, using project scope. Use the repository https://github.com/PeterPirog/mcp-light-memory. If the tool is not cloned yet, clone it to a stable location outside the project; if it already exists, update it with git pull --ff-only. Apply the canonical installation contract from the repository and run install.py with TARGET_PROJECT=C:\Projects\App and --client warp without --global. Do not force-overwrite an existing configuration. After installation, verify from cwd=C:\Projects\App: mlm.py --version, mlm.py status, and mlm.py guard, and confirm that the Warp configuration contains mcp-light-memory and the C:\Projects\App path. Report success only after MCP REGISTRATION: REGISTERED and successful verification. If Warp requires an additional project activation/toggle/approval, state the exact client-side step and do not claim the server is active before it is completed.

Warp — global client config for one project:

Install and configure MCP Light Memory (mcp-light-memory) in Warp globally for project C:\Projects\App. Use the repository https://github.com/PeterPirog/mcp-light-memory. If the tool is not cloned yet, clone it to a stable location outside the project; if it already exists, run git pull --ff-only. Apply the canonical installation contract and run install.py with TARGET_PROJECT=C:\Projects\App, --client warp, and --global. Remember: --global means the global Warp client configuration, while the server must still be bound to C:\Projects\App; do not use the multi-project router. After installation, verify from cwd=C:\Projects\App: mlm.py --version, mlm.py status, and mlm.py guard, and confirm that the global Warp configuration contains mcp-light-memory and the C:\Projects\App path. Report success only after MCP REGISTRATION: REGISTERED and successful verification.

OpenCode — install for one project (stable/V1):

Install and configure MCP Light Memory (mcp-light-memory) as an MCP server for project C:\Projects\App in OpenCode. By "OpenCode" I mean stable/V1, so use --client opencode, not opencode2. Use the repository https://github.com/PeterPirog/mcp-light-memory. If the tool is not cloned yet, clone it to a stable location outside the project; if it already exists, run git pull --ff-only. Run install.py with TARGET_PROJECT=C:\Projects\App and --client opencode without --global. Do not force-overwrite an existing configuration. If the installer returns MCP REGISTRATION: MANUAL_REQUIRED (for example because opencode.jsonc exists), do not report success: safely edit the JSONC while preserving comments and unrelated settings if you have appropriate file-editing tools; otherwise report the exact manual action required. After real registration, verify from cwd=C:\Projects\App: mlm.py --version, mlm.py status, and mlm.py guard, and confirm that the OpenCode configuration contains mcp-light-memory and C:\Projects\App.

OpenCode — global client config for one project (stable/V1):

Install and configure MCP Light Memory (mcp-light-memory) globally in OpenCode for project C:\Projects\App. By "OpenCode" I mean stable/V1, so use --client opencode. Use the repository https://github.com/PeterPirog/mcp-light-memory. If the tool is not cloned yet, clone it to a stable location outside the project; if it already exists, run git pull --ff-only. Run install.py with TARGET_PROJECT=C:\Projects\App, --client opencode, and --global. --global means the global OpenCode client configuration, while the server must still be bound only to C:\Projects\App; do not use the multi-project router. If the installer returns MCP REGISTRATION: MANUAL_REQUIRED, do not report success and follow the safe JSONC instructions. After real registration, verify from cwd=C:\Projects\App: mlm.py --version, mlm.py status, and mlm.py guard, and confirm that the global OpenCode configuration contains mcp-light-memory and the C:\Projects\App path.

For OpenCode 2 / V2, use the same prompts but explicitly say OpenCode 2 / V2 and require --client opencode2. More variants: docs/ZERO-SHOT-SETUP-PROMPTS.md.


Configuration details

Warp

Warp reads MCP server configs from ~/.warp/.mcp.json (global, auto-spawns) or {repo}/.warp/.mcp.json (project, requires a manual toggle per Warp docs). Shape: mcpServers.<name> with command, args, working_directory (always set it — the memory store is resolved from it). See examples/warp.example.json and docs/WARP-SETUP.md.

OpenCode stable (V1)

OpenCode reads opencode.json/.jsonc in the project root, or ~/.config/opencode/opencode.json globally. V1 servers are flat under mcp.<name> (no servers sub-key) with enabled: true and command as an array — see examples/opencode-legacy.example.json and docs/OPENCODE.md.

OpenCode 2 (V2, beta)

Same config files, different shape: mcp.servers.<name>, command as an array, and no enabled field (V2 disables via disabled: true) — see examples/opencode-v2.example.jsonc and docs/OPENCODE.md.

JetBrains AI Assistant / PyCharm

PyCharm does NOT auto-read any MCP config file. The installer prints ready-to-paste JSON + Working Directory; you add the server in Settings → Tools → AI Assistant → MCP (STDIO) and choose Server level = Project or Global. See examples/jetbrains.example.json.


Multi-project router

One MCP connection in front of many projects — registry allowlist, write:false hard boundary, per-call subprocess isolation.

Registry file (projects.json)

{
  "projects": {
    "backend": { "root": "/abs/path/backend", "write": true },
    "shared-lib": { "root": "/abs/path/shared-lib", "write": false }
  }
}

Warp config for the router

{
  "mcpServers": {
    "mcp-light-memory-router": {
      "command": "python3",
      "args": ["/abs/path/mcp-light-memory/.agents/skills/internal-rag/irag_mcp_router.py", "--registry", "/abs/path/projects.json"],
      "working_directory": "/abs/path/mcp-light-memory"
    }
  }
}

See docs/MCP-MULTI-PROJECT.md for details.


Workflow

context --task "current task"
  ↓
recovery, if required (RECOVERY REQUIRED)
  ↓
checkpoint before first change
  ↓
implementation
  ↓
checkpoint after each milestone
  ↓
guard before finishing

Core commands (CLI alias: mlm.py or legacy irag.py):

mlm.py context --task "..."
mlm.py checkpoint --reason "..."
mlm.py search --query "..." --limit 8
mlm.py remember --type decision --title "..." --body "..."
mlm.py show <ref>
mlm.py update <ref> --status superseded
mlm.py status
mlm.py guard
mlm.py validate
mlm.py doctor

Path mapping (rebrand: internal-rag → MCP Light Memory)

New name

Legacy path (kept for compatibility)

MCP Light Memory (product)

internal-rag (deprecated product name)

mlm / mlm.py (primary CLI)

irag.py (legacy alias, still works)

mcp-light-memory (MCP server name)

internal-rag (legacy, still works in configs)

mcp-light-memory-router (router name)

internal-rag-router (legacy)

INTERNAL_RAG/ (storage folder — unchanged)

—

.agents/skills/internal-rag/ (skill dir — unchanged)

—

The on-disk folder INTERNAL_RAG/ and the skill directory .agents/skills/internal-rag/ are intentionally kept under their legacy names for zero-migration backward compatibility. See docs/MIGRATION-TO-MCP-LIGHT-MEMORY.md.

Durable memory (CRUD)

remember --type decision --title "..." --body "..." --tags "a,b" --evidence "src/x.py:42" --links "decisions/other.md"
show <path-or-id>
show <ref> --section Knowledge
update <ref> --add-tags "new" --append "New evidence: ..."
supersede <ref> --by <new> --reason "..."
forget <ref>              # archives, does not delete
link --from <ref> --to <ref>
timeline --limit 20
status
history

Types: decision, knowledge, constraint, gotcha, failure, hypothesis, session.

Task stack (interrupts)

mlm.py push --task "interrupted work" --reason "user-priority"
mlm.py tasks
mlm.py resume
mlm.py forget-task <id>   # drop a specific task
mlm.py forget-task         # clear the whole stack

Configuration (.irag.yml, optional)

retrieval:
  limit: 10
  mmr_lambda: 0.4
  min_score: 0.3
  embeddings: auto        # auto | on | off
  profile: english-fast   # english-fast (default) | multilingual (PL/EN projects)
  embeddings_model: null  # explicit model overrides the profile
tokens:
  context_budget: 5000
checkpoints:
  auto_archive_sessions: true
  max_task_stack: 24

mlm.py config shows the effective configuration. mlm.py config --init writes a template.

Optional embeddings (better retrieval)

pip install -r requirements-optional.txt

When the package is available and .irag.yml has embeddings: auto (default), retrieval uses embeddings with fallback to BM25. Override at runtime with --embeddings on|off|auto.

Two retrieval profiles (see docs/EMBEDDINGS.md):

  • english-fast (default, all-MiniLM-L6-v2)

  • multilingual (intfloat/multilingual-e5-small) — for Polish-English projects

Offline / air-gapped

python pack.py --with-embeddings --profile english-fast
# -> internal-rag-offline-1.8.1.zip   (name from pack.py; 1.8.1 = VERSION file)
# On the air-gapped machine:
unzip internal-rag-offline-*.zip -d internal-rag-offline
pip install --no-index --find-links wheels/ -r requirements-optional.txt
python install.py "/path/to/project" --client <warp|opencode|opencode2|jetbrains>

See docs/OFFLINE.md for details.

Privacy & Git

The default install mode is local-only. The installer uses .git/info/exclude, not the project's .gitignore, so local memory and integration files are not accidentally committed.

Before publishing a project:

python .\privacy_check.py "D:\path\to\project"

Expected: RESULT: PASS

Full removal from a project

python .\uninstall.py "D:\path\to\project"

The uninstaller creates a backup outside the repository, then removes INTERNAL_RAG and its integrations. Use --keep-memory to preserve the memory data.

Documentation

Structure in a target project

project/
├── AGENTS.md
├── .irag.yml                    # optional config
├── INTERNAL_RAG/
│   ├── WORKING_STATE.md
│   ├── INDEX.md
│   ├── .checkpoint.json
│   ├── decisions/  knowledge/  gotchas/  failures/  hypotheses/  sessions/  archive/
│   └── exports/
├── .agents/skills/internal-rag/
│   ├── SKILL.md
│   ├── mlm.py                   # primary CLI (forwards to irag.py)
│   ├── irag.py                  # core (legacy alias, still the canonical module)
│   ├── irag_embeddings.py       # optional plugin
│   └── irag_hooks.py            # optional git hooks
└── .opencode/                   # OpenCode integration (optional)

Source of truth

  1. current user instructions, 2. current code/tests/configuration, 3. specifications/ADRs, 4. verified memory, 5. session notes, 6. hypotheses.

Memory can be stale. Code takes precedence.

License

MIT.


Changelog

1.8.0 — JetBrains manual setup

  • --client jetbrains no longer writes a fake config file (PyCharm ignores MCP config files). Prints ready-to-paste JSON + IDE menu instructions instead.

  • --unregister --client jetbrains prints a reminder to remove in the IDE UI.

1.7.2 — JetBrains cwd + client-specific messages

  • JetBrains: writes working_directory as a hint + prints WARNING with exact path to set in Settings → Tools → AI Assistant → MCP.

  • Client-specific restart messages (Restart PyCharm / Restart Warp / Restart OpenCode).

  • Memory store: <path> printed in install output for immediate verification.

1.7.1 — Windows Python stub fix

  • detect_python() rejects the WindowsApps 0-byte stub; prefers py -0p; verifies each candidate with --version.

  • Post-register verification: runs --version immediately after writing the config and reports PASS/FAIL.

  • --unregister deletes empty config files + parent dirs (fixes dead .warp/.mcp.json skeleton → GUARD STALE).

1.7.0 — Rebrand to MCP Light Memory

  • Total rebrand from internal-rag to MCP Light Memory (mcp-light-memory). New CLI alias mlm (mlm.py). Logo/icon assets. Migration doc. GitHub rebrand checklist.

  • Backward-compatible: irag.py, INTERNAL_RAG/, old MCP server names preserved as deprecated aliases.

  • 18 rebrand consistency tests.

1.6.1 — Post-v1.6 hardening

  • Mutation/lifecycle benchmark (11 scenarios). Trust boundary (ADR-015): trust: untrusted + security_flags. Evidence freshness (ADR-016): evidence_state. Scale benchmark (100/1k/10k). Router security regressions (+12 tests). Docs consistency test. 249 tests pass.

1.6.0 — Retrieval quality + MCP 2026-07-28

  • Memory-quality benchmark (37 cases). MCP 2026-07-28 dual-era (server/discover, _meta, structuredContent, outputSchema). Registry strict write. Sources in chunk prefix. Adaptive retrieval. Link-aware context. consolidate --prepare. Router latency benchmark. ADR-010…016.

1.5.0 — Abstention gate + multi-project router

  • Relevance/abstention gate (--meta). FTS5 candidate prefilter. Multi-project MCP router. MCP protocol hardening (pure stdout, SDK-verified). 168 tests.

1.4.0 — Chunking + dedup + temporal lifecycle

  • Section-aware chunking (schema v3). SimHash dedup. Multilingual PL/EN profile. Temporal lifecycle (valid_from/valid_to/supersedes/--at). consolidate --dry-run.

1.3.0 — Persistent embedding cache

  • Chunk-level float32 BLOBs in SQLite. Multiple models coexist. index --vacuum/--embed-missing.

1.0.2 — Token budget + privacy

  • Token budget enforcement. Stale memory detection. Duplicate detection. Privacy scan at write-time. Auto-checkpoint timer. Offline/air-gapped pack.

1.0.0 — Initial release

  • BM25 + MMR retrieval. Full memory CRUD. Task stack. MCP server (JSON-RPC stdio). Git hooks. Diagnostics. Export/import. Token budget.

Available Tools

8 tools
checkpointSave Task CheckpointA

Persist current operational task state so work can be resumed after interruption or context loss. Use at meaningful milestones and before ending a work session; use remember for reusable knowledge. This writes local checkpoint/task state, does not delete durable memories, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault
nextNoRecommended next action when work resumes.
phaseNoCurrent task phase or milestone name.
reasonYesWhy this checkpoint is being created.
blockersNoKnown blockers or unresolved issues.
completedNoWork completed since the previous checkpoint.
in_progressNoWork currently underway.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the safety profile (readOnly=false, destructive=false, openWorld=false), and the description adds the local-write scope, confirms no durable-memory deletion, and states no network access. It does not clarify whether checkpoints overwrite prior state or how the non-idempotent behavior manifests, so it is strong but not fully exhaustive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the core action, then usage and behavioral caveats. Every clause earns its place with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description adequately covers when to call it, what state it writes, and what it does not touch, which is sufficient for a checkpoint write. It could be slightly more complete on resume interaction with the sibling 'resume' tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all six parameters (reason, next, phase, blockers, completed, in_progress) are already documented in the schema. The description adds no parameter-level detail beyond what the structured fields provide, making the baseline 3 appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Persist current operational task state') with the added purpose of resuming after interruption or context loss. It explicitly distinguishes itself from the sibling 'remember' by noting that tool is for reusable knowledge, so an agent can tell them apart without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit when-to-use guidance ('at meaningful milestones and before ending a work session') and names the alternative ('use remember for reusable knowledge') with the condition that selects it. Nothing is left to inference about timing or routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

contextLoad Task ContextA

Start or resume a task by retrieving relevant durable project memories and current working state. Use before project changes or after a context reset; use search for a focused lookup. This call may update task or usage state, is non-idempotent, does not delete durable memories, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault
taskYesShort description of the task being started or resumed; used to retrieve relevant project context.
limitNoMaximum number of relevant memories to include in the context packet.

TDQS

A4.4/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, idempotentHint=false, openWorldHint=false, and destructiveHint=false, so part of the description ('non-idempotent', 'no network access') restates structured data. It does add value beyond them by disclosing what state is touched ('may update task or usage state') and a non-obvious negative guarantee ('does not delete durable memories').

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, no waste, with the core action front-loaded and usage/behavioral caveats packed into the second sentence. Every clause carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 2-parameter, non-destructive mutation with full annotation coverage and no output schema, the description covers trigger, alternative, state mutation, idempotency, and network behavior. It stops short of describing what the returned 'context packet' contains, a minor gap given no output schema is declared.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both 'task' and 'limit' are already documented in the schema. The description adds no syntax, format, or defaulting detail beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Start or resume a task') and resource ('durable project memories and current working state'), and explicitly routes the focused-lookup case to the sibling 'search'. An agent can distinguish it from search, resume, and checkpoint without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete triggers ('before project changes or after a context reset') and names the alternative tool and the condition that selects it ('use search for a focused lookup'). Nothing about when-to-use is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

guardCheck Checkpoint FreshnessA
Read-onlyIdempotent

Check whether project state changed since the last checkpoint. Use before finishing a task to detect uncheckpointed work, then checkpoint if stale. This operation is read-only and idempotent, does not modify memory or task state, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription
okYesTrue when project state is consistent with the last checkpoint.
fingerprintNoFingerprint representing the current project state used by the guard check.
changed_filesNoProject files detected as changed since the checkpoint baseline.

TDQS

A4.4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, and the description largely restates these facts ('read-only and idempotent', 'no network access'). It adds only marginal new context via 'does not modify memory or task state', which is implied by readOnlyHint. With annotations carrying the safety profile, this is adequate but adds little.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, with the core purpose and the usage trigger front-loaded before the safety caveat. The final sentence is largely redundant with the annotations, which slightly dilutes the otherwise tight structure.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, read-only check with an output schema present, the description covers purpose, when to call it, what to do with the result, and the safety profile. Return-value semantics are left to the output schema, which is appropriate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. No parameter-related claims are made or needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (check) and resource (whether project state changed since the last checkpoint), which is a distinct operation from the sibling 'checkpoint'. The name 'guard' is opaque on its own, but the description resolves it immediately.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly names the trigger ('Use before finishing a task to detect uncheckpointed work') and the conditional follow-up action ('then checkpoint if stale'), routing the agent to the sibling tool under a stated condition. Nothing is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

rememberStore Durable MemoryA

Store durable project knowledge that should survive across sessions. Use for stable decisions, constraints, gotchas, failures, hypotheses, or reusable knowledge; use checkpoint for temporary task progress. This writes local durable memory, does not delete existing memories, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault
bodyYesDurable content to preserve: a decision, fact, constraint, gotcha, failure, hypothesis, or reusable session knowledge.
tagsNoOptional comma-separated tags used to organize or retrieve the memory.
typeYesMemory category describing the kind of durable knowledge being stored.
scopeNoOptional scope describing where this memory applies.
titleYesShort, specific title for the memory.
statusNoMemory confidence state: active for established knowledge or tentative for information that still needs confirmation.
evidenceNoOptional source or project-relative evidence reference supporting the memory.
consequenceNoOptional impact or consequence of this memory for future work.

TDQS

A4.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description's behavioral claims ('does not delete existing memories', 'performs no network access') largely restate destructiveHint=false and openWorldHint=false from the annotations, and it adds the useful locality framing of 'local durable memory'. It does not disclose what the annotations cannot: whether repeated calls with identical content create duplicates (idempotentHint=false implies they do) or what the write returns. With annotations already carrying the safety profile, this is adequate but adds limited new context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with purpose, then usage routing, then behavioral constraints. No filler or repetition; every clause carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an 8-parameter write tool with full schema coverage, no output schema, and annotations present, the description covers purpose, usage routing, and side-effect profile. The only gap is duplicate/return behavior on a non-idempotent write, which is minor.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with per-field descriptions and enum values, so the schema does the heavy lifting. The description's list of knowledge kinds loosely maps to the type enum but adds no format, syntax, or selection guidance beyond it. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource (store durable project knowledge that survives across sessions) with the durable/temporary distinction made explicit against the checkpoint sibling. An agent can tell immediately what this tool produces and how it differs from checkpoint without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

States exactly when to use it (stable decisions, constraints, gotchas, failures, hypotheses, reusable knowledge) and names the alternative with its own condition (checkpoint for temporary task progress). Nothing is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

resumeResume Saved TaskA

Resume and remove the top saved task from the task stack. Use after tasks shows resumable work; use tasks when you only need to inspect the stack. This changes local task state, is non-idempotent, does not delete durable memories, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

TDQS

A4.6/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false and idempotentHint=false, but the description adds genuinely new context: it removes an entry from a stack (pop semantics), leaves durable memories intact, and performs no network access. The non-destructive clarification is valuable since 'remove' could otherwise read as data loss, though it restates non-idempotency already in annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, both front-loaded: the operation first, then routing guidance and behavioral guarantees. No filler, and every clause carries information an agent needs.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-param mutation with no output schema, the description covers the operation, the routing decision, state side effects, and network behavior. The only gap is what 'resume' returns (the resumed task content), which an agent might reasonably want to know, but annotations and description together are otherwise sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. No parameter-related claims are needed or missing.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a precise verb pair and resource: 'Resume and remove the top saved task from the task stack.' This distinguishes it from sibling 'tasks' (inspect) and from 'checkpoint'/'remember' by naming the exact stack operation performed.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly names the precondition ('Use after tasks shows resumable work') and the alternative ('use tasks when you only need to inspect the stack'). Both when-to-use and when-not-to-use are covered with the sibling named.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

statusInspect Memory StatusA
Read-onlyIdempotent

Return memory, checkpoint, index, and recovery status for the current project. Use for diagnostics and health checks. This operation is read-only and idempotent, does not modify memory or task state, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription
memoriesNoTotal number of durable memories in the current project.
checkpointsNoTotal number of checkpoints in the current project.
index_statusNoCurrent retrieval index health or synchronization status.
last_checkpointNoMost recent checkpoint recorded for the current project.

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, and the description largely restates these (read-only, idempotent, no state modification, no network access). It adds no information beyond the structured hints, but it also contradicts nothing, so a 3 is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the core action and scope, followed by usage and safety context. No filler and nothing repeated needlessly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The operation is parameterless, an output schema exists to describe the return shape, and annotations cover the safety profile; nothing an agent needs in order to call this correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing for the description to disambiguate; per the rubric, a 0-parameter tool has a 4 baseline. The description correctly avoids inventing inputs.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (Return) and enumerates the exact resources covered (memory, checkpoint, index, recovery status for the current project), which is well beyond a restatement of the name "status". It stops short of explicitly distinguishing itself from the operational siblings like resume or checkpoint, so it lands just under a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Use for diagnostics and health checks" gives a clear context for invoking it, implicitly steering the agent away from action-oriented siblings such as remember or resume. There are no explicit when-not conditions or named alternatives, which keeps it from a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

tasksList Pending TasksA
Read-onlyIdempotent

List the current task stack and resumable task state. Use before resume when you need to inspect pending work without changing the stack. This operation is read-only and idempotent, does not modify task state, and performs no network access.

ParametersJSON Schema
NameRequiredDescriptionDefault

No parameters

Output Schema

ParametersJSON Schema
NameRequiredDescription
tasksNoSaved or resumable tasks in the current task stack, in server-defined order.

TDQS

A4.1/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description's 'read-only and idempotent, does not modify task state' largely restates structured data rather than adding new behavior. 'Performs no network access' is a marginal addition but is already implied by openWorldHint=false.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the purpose in the first sentence and stays to three short sentences, though the safety restatement ('read-only and idempotent, does not modify task state') is somewhat redundant with annotations and could be trimmed.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the description need not explain return values, and it covers purpose, timing, and the safe-read nature adequately for a zero-parameter read tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so the baseline is 4; there is no parameter semantics to document, and the description correctly says nothing about inputs.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('List the current task stack and resumable task state') that an agent can distinguish from sibling tools like resume or status without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear timing guidance ('Use before resume when you need to inspect pending work') and implicitly contrasts with resume by noting it leaves the stack unchanged, but does not explicitly name alternatives or when-not-to-use conditions beyond that.

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.

  1. 8 tool updatesv0.1.0
    • First observedcheckpoint
    • First observedcontext
    • First observedguard
    • First observedremember
    • First observedresume
    • First observedsearch
    • First observedstatus
    • First observedtasks

TDQS

A4.2/5.0

Scored across 8 tools

Disambiguation4/5

Descriptions carefully cross-reference each other (checkpoint vs remember, context vs search, resume vs tasks) so boundaries are mostly clear. Minor potential overlap between checkpoint/remember and guard/status, but the descriptions resolve these distinctions well.

Naming Consistency4/5

All names are single lowercase words with no camelCase/snake_case mixing, giving a uniform visual style. However, it mixes verbs (checkpoint, resume, search, guard, remember) with nouns (context, status, tasks), so the convention is not fully predictable.

Tool Count5/5

Eight tools is well-scoped for a lightweight memory server, with each tool mapping to a distinct operation (write memory, write checkpoint, search, inspect, resume, diagnose). No tool feels redundant or bolted on.

Completeness4/5

Covers the core lifecycle: durable memory (remember/search), task state (checkpoint/context/resume/tasks), and diagnostics (status/guard). The one gap is the absence of an update/delete/forget operation for durable memories, which descriptions explicitly note they never remove, limiting correction of stale knowledge.

Maintenance

ActivitySlowing
ResponsivenessNo issues

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