firepass-mcp

MCP server that turns Kimi K2.6 Turbo into an agentic coding assistant. The model gets a tool loop — it can read/write files, run shell commands, and search code with ripgrep, ast-grep, jq, and glob — and iterates autonomously until the task is done.

Four tools exposed over MCP:

Requirements

• Python 3.10+

• A Fireworks AI API key

• rg (ripgrep), sg (ast-grep), jq, tree on PATH for full tool coverage

• bash, ls (standard on POSIX systems)

Related MCP server: kimi-code-mcp

Install

uvx firepass-mcp

Configuration

Set your API key:

export FIREWORKS_API_KEY="fw-..."

Codex CLI

Add the server with:

codex mcp add firepass --env FIREWORKS_API_KEY=fw-... -- uv run firepass-mcp

This writes a config like:

[mcp_servers.firepass]
command = "uv"
args = ["run", "firepass-mcp"]

[mcp_servers.firepass.env]
FIREWORKS_API_KEY = "fw-..."

Claude Code

Add the server with:

claude mcp add -e FIREWORKS_API_KEY=fw-... firepass -- uv run firepass-mcp

This writes a config like:

{
  "mcpServers": {
    "firepass": {
      "type": "stdio",
      "command": "uv",
      "args": ["run", "firepass-mcp"],
      "env": {
        "FIREWORKS_API_KEY": "fw-..."
      }
    }
  }
}

Claude Desktop / Generic MCP JSON

If your client reads MCP JSON directly, use:

{
  "mcpServers": {
    "firepass": {
      "command": "uvx",
      "args": ["firepass-mcp"],
      "env": {
        "FIREWORKS_API_KEY": "fw-..."
      }
    }
  }
}

Environment variables

How it works

1. You call firepass_worker, firepass_researcher, firepass_reviewer, or firepass_trio with a prompt and a required cwd

2. The server (server.py) sends the prompt to Kimi K2.6 Turbo with function-calling enabled, using tools.py for the typed ToolSpec registry and executors and messages.py for context budgeting

3. The model explores the codebase, makes edits, runs tests, and iterates

4. Every tool has a frozen-dataclass argument contract with additionalProperties: false enforced at runtime — unknown fields are rejected

5. When done, it calls done() with an executive summary

6. The summary (plus an activity log) is returned as the tool result

All roles get 60 iterations by default (capped at 200), configurable per call.

firepass_trio chains researcher, worker, and reviewer: the researcher gathers context, the worker implements, and the reviewer audits the result. The reviewer can send the worker back for fixes up to max_review_rounds times (default 2, capped at 5). The response is an XML envelope that contains each sub-result as a separate tag so the calling LLM can address them individually.

For Fireworks rate-limit behavior, worker fan-out guidance, and the recommended path before running many parallel workers, see docs/fireworks-scaling.md.

Response format

Every tool result is returned as an XML envelope so the calling LLM can read sub-results structurally.

Single tool (e.g. firepass_worker):

<firepass_worker status="completed" iterations="4" tool_calls="3">
  <result>Done: refactored auth logic into helpers.py</result>
  <activity>
    <call>read_file(path="src/auth.py")</call>
    <call>write_file(path="src/helpers.py", content="...")</call>
    <call>done(result="Done: refactored auth logic into helpers.py")</call>
  </activity>
</firepass_worker>

Trio call (firepass_trio):

<firepass_trio status="approved" rounds="1">
  <research status="completed" iterations="3" tool_calls="2">...</research>
  <rounds>
    <round n="1">
      <implementation status="completed" iterations="5" tool_calls="4">...</implementation>
      <review status="completed" iterations="2" tool_calls="1">...</review>
    </round>
  </rounds>
</firepass_trio>

Security model

All file operations (read_file, write_file, edit_file, glob_find, ripgrep, ast_grep, jq, tree, list_dir) are sandboxed to the required cwd you provide. Paths are resolved and validated against the working directory before any I/O.

The researcher and reviewer are read-only — bash, write_file, and edit_file are blocked both at the API schema level (model never sees them) and at runtime (server rejects them even if hallucinated). Dangerous ripgrep flags (--pre, --pre-glob, --search-zip, --replace, -r, -z) are also blocked.

The worker has full access including bash. It is not sandboxed at the command level — treat it like giving shell access to a remote developer scoped to your project directory.

Limits:

• File writes capped at 1 MB per operation

• File reads capped at 100K characters

• Tool output capped at 50K characters

• Context budget of 200K characters. Phase 1 truncates oldest tool outputs to [truncated]; phase 2 compacts assistant tool_call arguments to {}. If still over budget, an error is raised rather than silently exceeding.

• Configurable iteration limits (default 60 for all roles, capped at 200)

• Review rounds capped at 5 in the trio (default 2)

Development

Install dev dependencies and run tests:

uv sync
uv run pytest -q tests/test_server.py

Lint and type-check:

uv run ruff check src tests
uv run ty check src

License

MIT