Claude Code

Capture sessions and recall memory on every prompt in Claude Code, with hooks and an optional read-only MCP server.

For Claude Code, m3m0s is a set of hooks that all run m3m0s hook claude-code. Install the binary and store the credentials first, as described in CLI and credentials.

What the hooks do

Event	Role
`SessionStart`	Injects a digest of recent memories.
`UserPromptSubmit`	Two entries. A synchronous one with `--inject` searches memory by the prompt and injects the relevant hits. An async one captures.
`Stop`, `PreCompact`, `SessionEnd`	Capture the new part of the transcript (`PreCompact` and `SessionEnd` can be async).
`PostToolUse`	Optional safety net. It does nothing until the transcript has grown.

Async hooks cannot inject context, which is why the --inject entry must be synchronous.

Install the plugin

The plugin bundles all the hooks below and the read-only MCP server. Install the binary and ~/.m3m0s/hook.env first, then in Claude Code:

/plugin marketplace add rafaelvieiras/m3m0s
/plugin install m3m0s-memory@m3m0s

From the shell, the equivalent is claude plugin marketplace add rafaelvieiras/m3m0s followed by claude plugin install m3m0s-memory@m3m0s. If you already configured these hooks in settings.json, remove them first so everything does not run twice. The plugin covers the MCP server too, so skip the optional section below.

Or configure the hooks by hand

If you prefer not to use the plugin, add this to ~/.claude/settings.json:

{
  "hooks": {
    "SessionStart": [
      { "hooks": [{ "type": "command", "timeout": 15,
        "command": "m3m0s hook claude-code 2>>~/.m3m0s/hooks/claude-code.log || true" }] }
    ],
    "UserPromptSubmit": [
      { "hooks": [{ "type": "command", "timeout": 60, "async": true,
        "command": "m3m0s hook claude-code 2>>~/.m3m0s/hooks/claude-code.log || true" }] },
      { "hooks": [{ "type": "command", "timeout": 10,
        "command": "m3m0s hook claude-code --inject 2>>~/.m3m0s/hooks/claude-code.log || true" }] }
    ],
    "Stop": [
      { "hooks": [{ "type": "command", "timeout": 60,
        "command": "m3m0s hook claude-code 2>>~/.m3m0s/hooks/claude-code.log || true" }] }
    ],
    "PreCompact": [
      { "hooks": [{ "type": "command", "timeout": 60, "async": true,
        "command": "m3m0s hook claude-code 2>>~/.m3m0s/hooks/claude-code.log || true" }] }
    ],
    "SessionEnd": [
      { "hooks": [{ "type": "command", "timeout": 60, "async": true,
        "command": "m3m0s hook claude-code 2>>~/.m3m0s/hooks/claude-code.log || true" }] }
    ]
  }
}

Create the log directory once with mkdir -p ~/.m3m0s/hooks, then run m3m0s doctor to confirm the events are registered.

Optional: read-only MCP server (manual install only)

With capture and recall automatic, the agent only needs to search explicitly now and then. Register the MCP server in read-only mode, so it cannot add or rewrite memories:

claude mcp add m3m0s --scope user \
  -e M3M0S_URL=https://memory.example.com \
  -e M3M0S_API_KEY=<your API key> \
  -- m3m0s mcp --read-only

See MCP clients for the tools it exposes.

Verify

Open a new session in a project you have memories for and ask about something you decided earlier. A matching memory is injected before the model answers. Every injection is logged in ~/.m3m0s/hooks/claude-code.log.

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