The metrics endpoint

On the MCP server

memo-mcp serve --metrics-addr 127.0.0.1:9469
# or, in the client's server entry:  "env": { "MEMO_METRICS_ADDR": "127.0.0.1:9469" }

Claude Code example:

claude mcp add memo --env MEMO_KB=my-project --env MEMO_METRICS_ADDR=127.0.0.1:9469 -- /path/to/memo-mcp

At start, the server logs metrics listening url=http://127.0.0.1:9469/metrics.

Warning: one port, one process. The address is bound when the server starts. If a second session starts with the same entry while the first is running, for example two Claude Code windows on one project, the second fails with fatal: listen tcp 127.0.0.1:9469: bind: address already in use. Until this is relaxed:

• set --metrics-addr on one entry you use for a single long session;
• or give each knowledge base’s entry its own port;
• or leave it off and use the UI’s endpoint for file-level gauges plus the call log for per-call data.

On the UI

memo-mcp ui always serves GET /metrics, under the same guards as the rest of the UI: loopback, GET only, and the Host check. Pin the port to scrape it:

MEMO_KB=my-project memo-mcp ui --addr 127.0.0.1:9470 --no-model
curl -s http://127.0.0.1:9470/metrics | grep memo_kb_documents_live

--no-model keeps a long-running UI light. Its search is then keyword-only, which is fine for a metrics sidecar.

Checking it

curl -s http://127.0.0.1:9469/metrics | head -20
curl -s -o /dev/null -w '%{http_code}\n' -X POST http://127.0.0.1:9469/metrics   # 405
curl -s -o /dev/null -w '%{http_code}\n' -H 'Host: example.com' http://127.0.0.1:9469/metrics  # 403

memo_kb_* gauges are read from the database at scrape time and cached for 5 seconds, so frequent scrapes do not load the file. Read failures increment memo_store_status_scrape_errors_total.