harnessprotocol/memory

membrain Memory

Overview

Interface with the membrain knowledge graph — search entities, trace BFS traversals, add observations, create episodes, and check graph health.

Graceful degradation: If membrain MCP tools are not available, print install instructions and exit. If the HTTP server is not running, skip HTTP-dependent subcommands and say so.

Subcommands

Parse the argument after /memory to determine which operation to run.

| Invocation | Operation | |-----------|-----------| | /memory search <topic> | Search the graph for entities matching the topic | | /memory trace <query> | Run BFS traversal and display token savings | | /memory add <entity> <observation> | Add an observation to an existing entity | | /memory episode <text> | Create a timestamped episode from free text | | /memory status | Show graph statistics (entity/relation counts) | | /memory (no args) | Show usage and subcommand list |

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Step 1: Check MCP Availability

Before any graph operation, confirm membrain MCP tools are available.

Test: Can you call search_nodes? If the tool is missing from the tool list:

membrain MCP tools are not connected.

To connect them:
  1. Install mem: go install github.com/siracusa5/membrain/cmd/mem@latest
  2. Add to Claude Code settings (or via /plugin install membrain@harness-kit):
     {
       "mcpServers": {
         "membrain": { "command": "mem", "args": ["mcp"] }
       }
     }
  3. Restart Claude Code

For the desktop UI: mem serve   (opens http://localhost:3131)

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Step 2: Route to Subcommand

search <topic>

Search the graph for entities and relations related to the topic.

1. Call search_nodes with the topic as the query
2. If results < 3, try decomposing the topic into individual keywords and search each (max 2 additional calls)
3. Format results:

## Memory: "<topic>"

Found N entities  ·  saved X% tokens vs full graph dump

### <EntityName> (Type)
- observation 1
- observation 2
- observation 3

### <EntityName> (Type)
...

Relations: A → relationType → B

Caps: Max 10 entities shown. Max 3 observations per entity. Max 3 search_nodes calls.

If no results: "No entities found for '[topic]'. Try a broader term or check /memory status to confirm the graph has data."

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trace <query>

Run a BFS traversal to show how topics connect through the graph.

Requires: membrain server running on http://localhost:3131

1. Call GET http://localhost:3131/api/v1/trace?focus=<query> (URL-encode the query)
2. Parse the response — it includes traversal frames and token stats
3. Display:

## Trace: "<query>"

Traversal: N nodes  ·  depth D  ·  saved X% vs full dump

Starting node → relation → Node B → relation → Node C
                                               → relation → Node D
...

Token savings: retrieved ~X tokens of ~Y total (Z% saved)

Open in browser: http://localhost:3131/trace?focus=<query>

If the server is not running: "membrain server is not running. Start it with: mem serve"

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add <entity> <observation>

Add an observation to an existing entity in the graph.

Parse the argument: everything before the first quoted string or : is the entity name; the rest is the observation.

Examples:

• /memory add Claude "ships membrain MCP integration" → entity: Claude, obs: ships membrain MCP integration
• /memory add Claude: ships membrain MCP integration → same

1. Call add_observations with:

   [{ "entityName": "<entity>", "contents": ["<observation>"] }]
   

2. On success: "Added observation to <entity>."
3. If entity not found: "Entity '<entity>' not found. Create it first with create_entities or use /memory episode to capture a session."

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episode <text>

Create a timestamped episode capturing a chunk of session knowledge.

1. Extract a short name from the text (first sentence or ≤60 chars)
2. Scan the text for entity names that exist in the graph (use recent search_nodes results if available)
3. Call add_episode with:

   {
     "name": "<short-name> (YYYY-MM-DD)",
     "summary": "<full text>",
     "occurred_at": "<current ISO timestamp>",
     "mentioned_entities": ["Entity1", "Entity2"]
   }
   

   mentioned_entities auto-links the episode to existing graph entities — always include them when identifiable.
4. On success: "Episode created: <name>"

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status

Show graph health and statistics.

Requires: membrain server running on http://localhost:3131

1. Call GET http://localhost:3131/api/v1/graph/stats
2. Display:

## membrain Status

Entities:  N
Relations: N
Episodes:  N

Server:    http://localhost:3131  ✓
Graph:     <path to graph file>

Desktop UI:  http://localhost:3131/

If server not running: note that the server is offline and MCP-only stats are not available (membrain does not support entity count queries via MCP without the HTTP server).

---

No args

Print usage:

## /memory — membrain knowledge graph

  /memory search <topic>          search entities
  /memory trace <query>           BFS traversal with token stats
  /memory add <entity> <obs>      add an observation
  /memory episode <text>          create timestamped episode
  /memory status                  graph health and counts

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Common Mistakes

| Mistake | Fix | |---------|-----| | Calling read_graph | NEVER. Use search_nodes for all queries. | | Treating entity name as case-sensitive | membrain names are case-sensitive — match exact name from prior search results | | Running HTTP calls when server might be down | Always note if server is unreachable; MCP tools still work offline | | Showing raw JSON | Format output as human-readable markdown | | Exceeding search caps | Max 3 search_nodes calls per /memory search invocation |