Avalon Memory Crystal Server (amcs)

A Go MCP server for capturing and retrieving thoughts, memory, and project context. Exposes tools over Streamable HTTP, backed by Postgres with pgvector for semantic search.

What it does

• Capture thoughts with automatic embedding and metadata extraction
• Search thoughts semantically via vector similarity
• Organise thoughts into projects and retrieve full project context
• Summarise and recall memory across topics and time windows
• Link related thoughts and traverse relationships

Stack

• Go — MCP server over Streamable HTTP
• Postgres + pgvector — storage and vector search
• LiteLLM — primary hosted AI provider (embeddings + metadata extraction)
• OpenRouter — default upstream behind LiteLLM
• Ollama — supported local or self-hosted OpenAI-compatible provider

Tools

Tool	Purpose
capture_thought	Store a thought with embedding and metadata
search_thoughts	Semantic similarity search
list_thoughts	Filter thoughts by type, topic, person, date
thought_stats	Counts and top topics/people
get_thought	Retrieve a thought by ID
update_thought	Patch content or metadata
delete_thought	Hard delete
archive_thought	Soft delete
create_project	Register a named project
list_projects	List projects with thought counts
get_project_context	Recent + semantic context for a project
set_active_project	Set session project scope
get_active_project	Get current session project
summarize_thoughts	LLM prose summary over a filtered set
recall_context	Semantic + recency context block for injection
link_thoughts	Create a typed relationship between thoughts
related_thoughts	Explicit links + semantic neighbours

Configuration

Config is YAML-driven. Copy configs/config.example.yaml and set:

• database.url — Postgres connection string
• auth.mode — api_keys or oauth_client_credentials
• auth.keys — API keys for MCP access via x-brain-key or Authorization: Bearer <key> when auth.mode=api_keys
• auth.oauth.clients — client registry when auth.mode=oauth_client_credentials

OAuth Client Credentials flow (auth.mode=oauth_client_credentials):

1. Obtain a token — POST /oauth/token (public, no auth required):

   POST /oauth/token
   Content-Type: application/x-www-form-urlencoded
   Authorization: Basic base64(client_id:client_secret)
   
   grant_type=client_credentials
   

   Returns: {"access_token": "...", "token_type": "bearer", "expires_in": 3600}

2. Use the token on the MCP endpoint:

   Authorization: Bearer <access_token>
   

Alternatively, pass client_id and client_secret as body parameters instead of Authorization: Basic. Direct Authorization: Basic credential validation on the MCP endpoint is also supported as a fallback (no token required).

• ai.litellm.base_url and ai.litellm.api_key — LiteLLM proxy
• ai.ollama.base_url and ai.ollama.api_key — Ollama local or remote server

See llm/plan.md for full architecture and implementation plan.

Development

Run the SQL migrations against a local database with:

DATABASE_URL=postgres://... make migrate

LLM integration instructions are served at /llm.

Containers

The repo now includes a Dockerfile and Compose files for running the app with Postgres + pgvector.

1. Set a real LiteLLM key in your shell: export AMCS_LITELLM_API_KEY=your-key
2. Start the stack with your runtime: docker compose -f docker-compose.yml -f docker-compose.docker.yml up --build podman compose -f docker-compose.yml up --build
3. Call the service on http://localhost:8080

Notes:

• The app uses configs/docker.yaml inside the container.
• The local ./configs directory is mounted into /app/configs, so config edits apply without rebuilding the image.
• AMCS_LITELLM_BASE_URL overrides the LiteLLM endpoint, so you can retarget it without editing YAML.
• AMCS_OLLAMA_BASE_URL overrides the Ollama endpoint for local or remote servers.
• The Compose stack uses a default bridge network named amcs.
• The base Compose file uses host.containers.internal, which is Podman-friendly.
• The Docker override file adds host-gateway aliases so Docker can resolve the same host endpoint.
• Database migrations 001 through 005 run automatically when the Postgres volume is created for the first time.
• migrations/006_rls_and_grants.sql is intentionally skipped during container bootstrap because it contains deployment-specific grants for a role named amcs_user.

Ollama

Set ai.provider: "ollama" to use a local or self-hosted Ollama server through its OpenAI-compatible API.

Example:

ai:
  provider: "ollama"
  embeddings:
    model: "nomic-embed-text"
    dimensions: 768
  metadata:
    model: "llama3.2"
    temperature: 0.1
  ollama:
    base_url: "http://localhost:11434/v1"
    api_key: "ollama"
    request_headers: {}

Notes:

• For remote Ollama servers, point ai.ollama.base_url at the remote /v1 endpoint.
• The client always sends Bearer auth; Ollama ignores it locally, so api_key: "ollama" is a safe default.
• ai.embeddings.dimensions must match the embedding model you actually use, or startup will fail the database vector-dimension check.