# Avalon Memory Crystal Server  (amcs)

![Avalon Memory Crystal](assets/avelonmemorycrystal.jpg)

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; uses explicit `project` or the active session project |
| `set_active_project` | Set session project scope; requires a stateful MCP session |
| `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 |
| `upload_file` | Stage a file from a server-side path or base64 and get an `amcs://files/{id}` resource URI |
| `save_file` | Store a file (base64 or resource URI) and optionally link it to a thought |
| `load_file` | Retrieve a stored file by ID; returns metadata, base64 content, and an embedded MCP binary resource |
| `list_files` | Browse stored files by thought, project, or kind |
| `backfill_embeddings` | Generate missing embeddings for stored thoughts |
| `reparse_thought_metadata` | Re-extract and normalize metadata for stored thoughts |
| `retry_failed_metadata` | Retry metadata extraction for thoughts still pending or failed |
| `add_skill` | Store a reusable agent skill (behavioural instruction or capability prompt) |
| `remove_skill` | Delete an agent skill by id |
| `list_skills` | List all agent skills, optionally filtered by tag |
| `add_guardrail` | Store a reusable agent guardrail (constraint or safety rule) |
| `remove_guardrail` | Delete an agent guardrail by id |
| `list_guardrails` | List all agent guardrails, optionally filtered by tag or severity |
| `add_project_skill` | Link an agent skill to a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `remove_project_skill` | Unlink an agent skill from a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `list_project_skills` | List all skills linked to a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `add_project_guardrail` | Link an agent guardrail to a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `remove_project_guardrail` | Unlink an agent guardrail from a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `list_project_guardrails` | List all guardrails linked to a project; pass `project` explicitly if your client does not preserve MCP sessions |
| `get_version_info` | Return the server build version information, including version, tag name, commit, and build date |
| `describe_tools` | List all available MCP tools with names, descriptions, categories, and model-authored usage notes; call this at the start of a session to orient yourself |
| `annotate_tool` | Persist your own usage notes for a specific tool; notes are returned by `describe_tools` in future sessions |

## Self-Documenting Tools

AMCS includes a built-in tool directory that models can read and annotate.

**`describe_tools`** returns every registered tool with its name, description, category, and any model-written notes. Call it with no arguments to get the full list, or filter by category:

```json
{ "category": "thoughts" }
```

Available categories: `system`, `thoughts`, `projects`, `files`, `admin`, `household`, `maintenance`, `calendar`, `meals`, `crm`, `skills`, `chat`, `meta`.

**`annotate_tool`** lets a model write persistent usage notes against a tool name. Notes survive across sessions and are returned by `describe_tools`:

```json
{ "tool_name": "capture_thought", "notes": "Always pass project explicitly — session state is not reliable in this client." }
```

Pass an empty string to clear notes. The intended workflow is:

1. At the start of a session, call `describe_tools` to discover tools and read accumulated notes.
2. As you learn something non-obvious about a tool — a gotcha, a workflow pattern, a required field ordering — call `annotate_tool` to record it.
3. Future sessions receive the annotation automatically via `describe_tools`.

## MCP Error Contract

AMCS returns structured JSON-RPC errors for common MCP failures. Clients should branch on both `error.code` and `error.data.type` instead of parsing the human-readable message.

### Stable error codes

| Code | `data.type` | Meaning |
|---|---|---|
| `-32602` | `invalid_arguments` | MCP argument/schema validation failed before the tool handler ran |
| `-32602` | `invalid_input` | Tool-level input validation failed inside the handler |
| `-32050` | `session_required` | Tool requires a stateful MCP session |
| `-32051` | `project_required` | No explicit `project` was provided and no active session project was available |
| `-32052` | `project_not_found` | The referenced project does not exist |
| `-32053` | `invalid_id` | A UUID-like identifier was malformed |
| `-32054` | `entity_not_found` | A referenced entity such as a thought or contact does not exist |

### Error data shape

AMCS may include these fields in `error.data`:

- `type` — stable machine-readable error type
- `field` — single argument name such as `name`, `project`, or `thought_id`
- `fields` — multiple argument names for one-of or mutually-exclusive validation
- `value` — offending value when safe to expose
- `detail` — validation detail such as `required`, `invalid`, `one_of_required`, `mutually_exclusive`, or a schema validation message
- `hint` — remediation guidance
- `entity` — entity name for generic not-found errors

Example schema-level error:

```json
{
  "code": -32602,
  "message": "invalid tool arguments",
  "data": {
    "type": "invalid_arguments",
    "field": "name",
    "detail": "validating root: required: missing properties: [\"name\"]",
    "hint": "check the name argument"
  }
}
```

Example tool-level error:

```json
{
  "code": -32051,
  "message": "project is required; pass project explicitly or call set_active_project in this MCP session first",
  "data": {
    "type": "project_required",
    "field": "project",
    "hint": "pass project explicitly or call set_active_project in this MCP session first"
  }
}
```

### Client example

Go client example handling AMCS MCP errors:

```go
result, err := session.CallTool(ctx, &mcp.CallToolParams{
    Name:      "get_project_context",
    Arguments: map[string]any{},
})
if err != nil {
    var rpcErr *jsonrpc.Error
    if errors.As(err, &rpcErr) {
        var data struct {
            Type  string `json:"type"`
            Field string `json:"field"`
            Hint  string `json:"hint"`
        }
        _ = json.Unmarshal(rpcErr.Data, &data)

        switch {
        case rpcErr.Code == -32051 && data.Type == "project_required":
            // Retry with an explicit project, or call set_active_project first.
        case rpcErr.Code == -32602 && data.Type == "invalid_arguments":
            // Ask the caller to fix the malformed arguments.
        }
    }
}
_ = result
```

## Build Versioning

AMCS embeds build metadata into the binary at build time.

- `version` is generated from the current git tag when building from a tagged commit
- `tag_name` is the repo tag name, for example `v1.0.1`
- `build_date` is the UTC build timestamp in RFC3339 format
- `commit` is the short git commit SHA

For untagged builds, `version` and `tag_name` fall back to `dev`.

Use `get_version_info` to retrieve the runtime build metadata:

```json
{
  "server_name": "amcs",
  "version": "v1.0.1",
  "tag_name": "v1.0.1",
  "commit": "abc1234",
  "build_date": "2026-03-31T14:22:10Z"
}
```

## Agent Skills and Guardrails

Skills and guardrails are reusable agent behaviour instructions and constraints that can be attached to projects.

**At the start of every project session, always call `list_project_skills` and `list_project_guardrails` first.** Use the returned skills and guardrails to guide agent behaviour for that project. Only generate or create new skills/guardrails if none are returned. If your MCP client does not preserve sessions across calls, pass `project` explicitly instead of relying on `set_active_project`.

### Skills

A skill is a reusable behavioural instruction or capability prompt — for example, "always respond in structured markdown" or "break complex tasks into numbered steps before starting".

```json
{ "name": "structured-output", "description": "Enforce markdown output format", "content": "Always structure responses using markdown headers and bullet points.", "tags": ["formatting"] }
```

### Guardrails

A guardrail is a constraint or safety rule — for example, "never delete files without explicit confirmation" or "do not expose secrets in output".

```json
{ "name": "no-silent-deletes", "description": "Require confirmation before deletes", "content": "Never delete, drop, or truncate data without first confirming with the user.", "severity": "high", "tags": ["safety"] }
```

Severity levels: `low`, `medium`, `high`, `critical`.

### Project linking

Link existing skills and guardrails to a project so they are automatically available when that project is active:

```json
{ "project": "my-project", "skill_id": "<uuid>" }
{ "project": "my-project", "guardrail_id": "<uuid>" }
```

## 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`
- `mcp.version` is build-generated and should not be set in config

**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.

## Backfill

Run `backfill_embeddings` after switching embedding models or importing thoughts without vectors.

```json
{
  "project": "optional-project-name",
  "limit": 100,
  "include_archived": false,
  "older_than_days": 0,
  "dry_run": false
}
```

- `dry_run: true` — report counts without calling the embedding provider
- `limit` — max thoughts per call (default 100)
- Embeddings are generated in parallel (4 workers) and upserted; one failure does not abort the run

## Metadata Reparse

Run `reparse_thought_metadata` to fix stale or inconsistent metadata by re-extracting it from thought content.

```json
{
  "project": "optional-project-name",
  "limit": 100,
  "include_archived": false,
  "older_than_days": 0,
  "dry_run": false
}
```

- `dry_run: true` scans only and does not call metadata extraction or write updates
- If extraction fails for a thought, existing metadata is normalized and written only if it changes
- Metadata reparse runs in parallel (4 workers); one failure does not abort the run

## Failed Metadata Retry

`capture_thought` now stores the thought even when metadata extraction times out or fails. Those thoughts are marked with `metadata_status: "pending"` and retried in the background. Use `retry_failed_metadata` to sweep any thoughts still marked `pending` or `failed`.

```json
{
  "project": "optional-project-name",
  "limit": 100,
  "include_archived": false,
  "older_than_days": 1,
  "dry_run": false
}
```

- `dry_run: true` scans only and does not call metadata extraction or write updates
- successful retries mark the thought metadata as `complete` and clear the last error
- failed retries update the retry markers so the daily sweep can pick them up again later

## File Storage

Files can optionally be linked to a thought by passing `thought_id`, which also adds an attachment reference to that thought's metadata. AI clients should prefer `save_file` when the goal is to retain the artifact itself, rather than reading or summarizing the file first. Stored files and attachment metadata are not forwarded to the metadata extraction client.

### MCP tools

**Stage a file and get a URI** (`upload_file`) — preferred for large or binary files:

```json
{
  "name": "diagram.png",
  "content_path": "/absolute/path/to/diagram.png"
}
```

Or with base64 for small files (≤10 MB):

```json
{
  "name": "diagram.png",
  "content_base64": "<base64-payload>"
}
```

Returns `{"file": {...}, "uri": "amcs://files/<id>"}`. Pass `thought_id`/`project` to link immediately, or omit them and use the URI in a later `save_file` call.

**Link a staged file to a thought** (`save_file` with `content_uri`):

```json
{
  "name": "meeting-notes.pdf",
  "thought_id": "optional-thought-uuid",
  "content_uri": "amcs://files/<id-from-upload_file>"
}
```

**Save small files inline** (`save_file` with `content_base64`, ≤10 MB):

```json
{
  "name": "meeting-notes.pdf",
  "media_type": "application/pdf",
  "kind": "document",
  "thought_id": "optional-thought-uuid",
  "content_base64": "<base64-payload>"
}
```

`content_base64` and `content_uri` are mutually exclusive in both tools.

**Load a file** — returns metadata, base64 content, and an embedded MCP binary resource (`amcs://files/{id}`). The `id` field accepts either the bare stored file UUID or the full `amcs://files/{id}` URI:

```json
{ "id": "stored-file-uuid" }
```

**List files** for a thought or project:

```json
{
  "thought_id": "optional-thought-uuid",
  "project": "optional-project-name",
  "kind": "optional-image-document-audio-file",
  "limit": 20
}
```

### MCP resources

Stored files are also exposed as MCP resources at `amcs://files/{id}`. MCP clients can read raw binary content directly via `resources/read` without going through `load_file`.

### HTTP upload and download

Direct HTTP access avoids base64 encoding entirely. The Go server caps `/files` uploads at 100 MB per request. Large uploads are also subject to available memory, Postgres limits, and any reverse proxy or load balancer in front of AMCS.

Multipart upload:

```bash
curl -X POST http://localhost:8080/files \
  -H "x-brain-key: <key>" \
  -F "file=@./diagram.png" \
  -F "project=amcs" \
  -F "kind=image"
```

Raw body upload:

```bash
curl -X POST "http://localhost:8080/files?project=amcs&name=meeting-notes.pdf" \
  -H "x-brain-key: <key>" \
  -H "Content-Type: application/pdf" \
  --data-binary @./meeting-notes.pdf
```

Binary download:

```bash
curl http://localhost:8080/files/<id> \
  -H "x-brain-key: <key>" \
  -o meeting-notes.pdf
```

**Automatic backfill** (optional, config-gated):

```yaml
backfill:
  enabled: true
  run_on_startup: true   # run once on server start
  interval: "15m"        # repeat every 15 minutes
  batch_size: 20
  max_per_run: 100
  include_archived: false
```

```yaml
metadata_retry:
  enabled: true
  run_on_startup: true   # retry failed metadata once on server start
  interval: "24h"        # retry pending/failed metadata daily
  max_per_run: 100
  include_archived: false
```

**Search fallback**: when no embeddings exist for the active model in scope, `search_thoughts`, `recall_context`, `get_project_context`, `summarize_thoughts`, and `related_thoughts` automatically fall back to Postgres full-text search so results are never silently empty.

## Client Setup

### Claude Code

```bash
# API key auth
claude mcp add --transport http amcs http://localhost:8080/mcp --header "x-brain-key: <key>"

# Bearer token auth
claude mcp add --transport http amcs http://localhost:8080/mcp --header "Authorization: Bearer <token>"
```

### OpenAI Codex

Add to `~/.codex/config.toml`:

```toml
[[mcp_servers]]
name = "amcs"
url  = "http://localhost:8080/mcp"

[mcp_servers.headers]
x-brain-key = "<key>"
```

### OpenCode

```bash
# API key auth
opencode mcp add --name amcs --type remote --url http://localhost:8080/mcp --header "x-brain-key=<key>"

# Bearer token auth
opencode mcp add --name amcs --type remote --url http://localhost:8080/mcp --header "Authorization=Bearer <token>"
```

Or add directly to `opencode.json` / `~/.config/opencode/config.json`:

```json
{
  "mcp": {
    "amcs": {
      "type": "remote",
      "url": "http://localhost:8080/mcp",
      "headers": {
        "x-brain-key": "<key>"
      }
    }
  }
}
```

## Apache Proxy

If AMCS is deployed behind Apache HTTP Server, configure the proxy explicitly for larger uploads and longer-running requests.

Example virtual host settings for the current AMCS defaults:

```apache
<VirtualHost *:443>
    ServerName amcs.example.com

    ProxyPreserveHost On
    LimitRequestBody 104857600
    RequestReadTimeout handshake=0 header=20-40,MinRate=500 body=600,MinRate=500
    Timeout 600
    ProxyTimeout 600

    ProxyPass        /mcp   http://127.0.0.1:8080/mcp   connectiontimeout=30 timeout=600
    ProxyPassReverse /mcp   http://127.0.0.1:8080/mcp

    ProxyPass        /files http://127.0.0.1:8080/files connectiontimeout=30 timeout=600
    ProxyPassReverse /files http://127.0.0.1:8080/files
</VirtualHost>
```

Recommended Apache settings:

- `LimitRequestBody 104857600` matches AMCS's 100 MB `/files` upload cap.
- `RequestReadTimeout ... body=600` gives clients up to 10 minutes to send larger request bodies.
- `ProxyTimeout 600` and `ProxyPass ... timeout=600` give Apache enough time to wait for the Go backend.
- If another proxy or load balancer sits in front of Apache, align its size and timeout settings too.

## 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:

```yaml
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.
