fleet-memory/hindsight-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
..
hindsight_api Harden MCP server: fix routing, validation, and usage metering (#341) 2026-02-11 10:41:20 +01:00
tests Harden MCP server: fix routing, validation, and usage metering (#341) 2026-02-11 10:41:20 +01:00
pyproject.toml feat: add otel traceability (#330) 2026-02-10 12:20:48 +01:00
README.md feat(doc): add new config options and supported providers (#84) 2026-01-01 17:09:05 +01:00

Hindsight API

Memory System for AI Agents — Temporal + Semantic + Entity Memory Architecture using PostgreSQL with pgvector.

Hindsight gives AI agents persistent memory that works like human memory: it stores facts, tracks entities and relationships, handles temporal reasoning ("what happened last spring?"), and forms opinions based on configurable disposition traits.

Installation

pip install hindsight-api

Quick Start

Run the Server

# Set your LLM provider
export HINDSIGHT_API_LLM_PROVIDER=openai
export HINDSIGHT_API_LLM_API_KEY=sk-xxxxxxxxxxxx

# Start the server (uses embedded PostgreSQL by default)
hindsight-api

The server starts at http://localhost:8888 with:

  • REST API for memory operations
  • MCP server at /mcp for tool-use integration

Use the Python API

from hindsight_api import MemoryEngine

# Create and initialize the memory engine
memory = MemoryEngine()
await memory.initialize()

# Create a memory bank for your agent
bank = await memory.create_memory_bank(
    name="my-assistant",
    background="A helpful coding assistant"
)

# Store a memory
await memory.retain(
    memory_bank_id=bank.id,
    content="The user prefers Python for data science projects"
)

# Recall memories
results = await memory.recall(
    memory_bank_id=bank.id,
    query="What programming language does the user prefer?"
)

# Reflect with reasoning
response = await memory.reflect(
    memory_bank_id=bank.id,
    query="Should I recommend Python or R for this ML project?"
)

CLI Options

hindsight-api --help

# Common options
hindsight-api --port 9000          # Custom port (default: 8888)
hindsight-api --host 127.0.0.1     # Bind to localhost only
hindsight-api --workers 4          # Multiple worker processes
hindsight-api --log-level debug    # Verbose logging

Configuration

Configure via environment variables:

Variable Description Default
HINDSIGHT_API_DATABASE_URL PostgreSQL connection string pg0 (embedded)
HINDSIGHT_API_LLM_PROVIDER openai, anthropic, gemini, groq, ollama, lmstudio openai
HINDSIGHT_API_LLM_API_KEY API key for LLM provider -
HINDSIGHT_API_LLM_MODEL Model name gpt-4o-mini
HINDSIGHT_API_HOST Server bind address 0.0.0.0
HINDSIGHT_API_PORT Server port 8888

Example with External PostgreSQL

export HINDSIGHT_API_DATABASE_URL=postgresql://user:pass@localhost:5432/hindsight
export HINDSIGHT_API_LLM_PROVIDER=groq
export HINDSIGHT_API_LLM_API_KEY=gsk_xxxxxxxxxxxx

hindsight-api

Docker

docker run --rm -it -p 8888:8888 \
  -e HINDSIGHT_API_LLM_API_KEY=$OPENAI_API_KEY \
  -v $HOME/.hindsight-docker:/home/hindsight/.pg0 \
  ghcr.io/vectorize-io/hindsight:latest

MCP Server

For local MCP integration without running the full API server:

hindsight-local-mcp

This runs a stdio-based MCP server that can be used directly with MCP-compatible clients.

Key Features

  • Multi-Strategy Retrieval (TEMPR) — Semantic, keyword, graph, and temporal search combined with RRF fusion
  • Entity Graph — Automatic entity extraction and relationship tracking
  • Temporal Reasoning — Native support for time-based queries
  • Disposition Traits — Configurable skepticism, literalism, and empathy influence opinion formation
  • Three Memory Types — World facts, bank actions, and formed opinions with confidence scores

Documentation

Full documentation: https://hindsight.vectorize.io

License

Apache 2.0