That shape keeps the context cost of installing it small while the reach stays wide, and it moves the learning curve from tool names to operation names — which is why the schema lookup exists as a call you make before writing. Two behaviours to plan around: an experiment run is fire-and-return, with the work continuing server-side, so progress is something you go back and read; and Ollie's own mid-stream writes execute without asking by default — set OPIK_MCP_AUTO_APPROVE=disabled if you want each one confirmed first.
Comet's server over an Opik tracing and evaluation workspace, shaped as six general verbs — read, list, write, schema, run_experiment and ask_ollie — rather than a tool per endpoint.
- Any entity read by UUID, name or opik:// URI, with adaptive compression and a max_tokens ceiling on what comes back
- Entity listings as a pipe-delimited table with a pagination footer, filtered by name and scoped to a project where the type requires one
- Writes through a single operation-selected tool: traces and spans logged, scores and comments attached, prompt versions saved, test suites and experiments managed — one object or a batch of up to 1000
- A dry run before committing and an idempotency key so a retried write does not double-log
- The JSON Schema, OAuth scope and one validated example for a write operation's payload, as a pure lookup with no backend call
- Experiments submitted against a test-suite-backed dataset, returning experiment ids immediately while the run continues server-side
- Ollie asked directly for investigative and cross-entity questions, returning its answer plus a thread id to continue in
Python 3.13 or newer and uv, since it runs as uvx opik-mcp. OPIK_API_KEY from your Comet settings, and OPIK_WORKSPACE set to the workspace name as it appears in the URL — on cloud with an API key, leaving it unset sends default, and reads come back from your account's default workspace rather than failing. Leave it unset over OAuth and on the open-source build, where default is the only workspace. Self-hosted deployments point at their own host with COMET_URL_OVERRIDE, and there ask_ollie and run_experiment are unavailable — they are Comet Cloud only. Apache-2.0.
One command plus a key — uvx opik-mcp@latest, then supply credentials