fleet-memory/hindsight-api/hindsight_api/api
DK09876 e798979733
Harden MCP server: fix routing, validation, and usage metering (#341)
* fix: move mental model usage metering into engine for MCP support

Mental model validation hooks (validate_mental_model_get, validate_mental_model_refresh)
were only called in REST HTTP handlers, not in the engine. MCP tools call engine methods
directly, so usage metering was skipped entirely for MCP mental model operations.

Moved pre-validation and post-completion hooks into memory_engine.py (matching the
retain/recall/reflect pattern) and removed the duplicate code from http.py.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: remove double validation from create_mental_model and add internal checks

- Remove pre-validation from create_mental_model since callers always call
  submit_async_refresh_mental_model next (which validates), preventing
  double credit checks
- Add is_internal checks to mental model metering validators (matching
  the existing pattern for recall/reflect) so background worker tasks
  skip billing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: prevent 307 redirect on /mcp that breaks MCP tool discovery

Starlette's Mount class redirects /mcp to /mcp/ with a 307 Temporary
Redirect. Many MCP clients don't follow POST redirects, which causes
tool discovery to fail (0 tools discovered despite successful auth).

Add _MCPPathRewriteMiddleware that rewrites /mcp to /mcp/ at the ASGI
level before routing, preventing the redirect entirely. Both /mcp and
/mcp/ now work identically.

Add regression test test_mcp_no_trailing_slash_works to verify URLs
with and without trailing slashes discover tools correctly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* harden MCP server for real-world usage

- Remove MCP_ENDPOINTS blocklist so banks named "sse"/"messages" route correctly
- Scope SSE body rewriting to text/event-stream responses only to prevent data corruption
- Add _validate_mental_model_inputs for name, source_query, max_tokens validation in MCP tools
- Improve "not found" error messages to include bank_id context
- Fix fragile tool count assertions (exact → minimum bounds)
- Add integration tests: tool execution, input validation, edge-case bank names
- Add unit tests for validation helper and tool-level validation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* refactor: replace Mount + rewrite middleware with wrapping middleware

Starlette's Mount class redirects /mcp -> /mcp/ with 307, which MCP clients
don't follow. Previously we patched this with _MCPPathRewriteMiddleware.

Now MCPMiddleware wraps the FastAPI app directly via add_middleware, intercepting
/mcp* requests before they reach Starlette's router. No Mount means no redirect.

- Remove _MCPPathRewriteMiddleware (no longer needed)
- Remove app.mount() call
- Add prefix parameter to MCPMiddleware
- Use app.add_middleware() for proper Starlette integration
- Simplify path stripping (just remove prefix, no mount/root_path handling)
- Update routing test to match current behavior (no MCP_ENDPOINTS blocklist)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: update stale docstring referencing removed _MCPPathRewriteMiddleware

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-11 10:41:20 +01:00
..
__init__.py Harden MCP server: fix routing, validation, and usage metering (#341) 2026-02-11 10:41:20 +01:00
http.py feat: add mental model CRUD tools to MCP server (#337) 2026-02-10 22:40:43 +01:00
mcp.py Harden MCP server: fix routing, validation, and usage metering (#341) 2026-02-11 10:41:20 +01:00