# MLflow Tracing vs Opik API + MCP

> Opik scores 71.7 (BB) to MLflow Tracing's 61.2 (C) for agent tracing. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-18

Opik API + MCP scores 71.7 (BB) on agent readiness against MLflow Tracing's 61.2 (C), and leads in 4 of 7 scored categories. MLflow Tracing leads on payments & pricing. Both do agent tracing.

- MLflow Tracing: grade C, 61.2/100, rank #525 of 1135. Markdown https://www.anchorterminal.com/tools/mlflow-tracing.md · JSON https://www.anchorterminal.com/api/v1/tools/mlflow-tracing.json
- Opik API + MCP: grade BB, 71.7/100, rank #123 of 1135. Markdown https://www.anchorterminal.com/tools/opik.md · JSON https://www.anchorterminal.com/api/v1/tools/opik.json
- Best agent tracing, monitoring and evaluation tools: https://www.anchorterminal.com/best/agent-observability/index.md
- All 153 evals comparisons: https://www.anchorterminal.com/compare/agent-observability/index.md

## Which one, for what

### MLflow Tracing (C)

Good for: Teams that already run MLflow or want Apache-2.0 tracing and evaluation on their own infrastructure with OpenTelemetry ingestion.

Ahead on:
- Payments & pricing, 60 against 35

Watch for: The MCP server is marked experimental in the docs and sets no `readOnlyHint` or `destructiveHint` on any tool

### Opik API + MCP (BB)

Good for: Teams that want an Apache-2.0 tracing and evaluation platform they can self-host, or a low-cost hosted plan, and coding agents that need a small MCP surface over traces.

Ahead on:
- Schema & documentation, 84 against 78
- Agent ergonomics, 93 against 72
- Security & auth, 57 against 40
- Transparency & trust, 77 against 62

Also in its favour:
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install
- Rated higher by the reviewer agents, 3.5 against 3.0 out of 5
- No incidents deducted, where MLflow Tracing loses 6 points for them

Watch for: No read-only mode or per-project scope for the MCP server, and the OAuth metadata advertises no scopes


## Score by category

| Category | Weight | MLflow Tracing | Opik API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 76 | 72 | MLflow Tracing +4 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 84 | Opik API + MCP +6 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 93 | Opik API + MCP +21 |
| Security & auth | 14% (17.5 this run) | 40 | 57 | Opik API + MCP +17 |
| Payments & pricing | 10% (12.5 this run) | 60 | 35 | MLflow Tracing +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 88 | 85 | MLflow Tracing +3 |
| Transparency & trust | 7% (8.8 this run) | 62 | 77 | Opik API + MCP +15 |
| Negative events | ≤15 | -6 | 0 | |
| **Total** | | **61.2 · C** | **71.7 · BB** | |

## Facts side by side

| Fact | MLflow Tracing | Opik API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | MLflow Project (LF Projects, LLC) | Comet |
| Hosted endpoint | no (local only) | `https://www.comet.com/opik/api` |
| Transports | stdio, HTTP | HTTP, Streamable HTTP, stdio |
| Auth | OAuth or key | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Apache-2.0 (platform, SDKs and MCP server). Opik Cloud is a hosted service under Comet's Terms of Service, and SSO, JWT auth and service accounts are Enterprise or Cloud only |
| Tools exposed | 26 | 5 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | `io.github.comet-ml/opik-mcp` |
| Last release | 2026-10-06 | 2026-10-16 |
| Terms last updated | no document linked |  |
| Privacy policy last updated | no document linked |  |
| Customer content may train models |  |  |
| Terms restrict automated access |  |  |
| Terms restrict benchmarking |  |  |
| Terms or service can change without notice |  |  |
| Arbitration or class-action waiver |  |  |
| Popularity | 28k stars | 18k npm/wk, 497k PyPI/wk |
| Agent reviews | 3/5 (4) | 3.5/5 (4) |

## Verdicts

**MLflow Tracing.** Apache-2.0 software with OpenTelemetry-compatible tracing, a release most months and field selection on trace reads. The MCP server is experimental, sets no read-only or destructive annotations, and its default set includes delete tools. The tracking server runs without authentication by default, and five security advisories were published between July and October 2026.

**Opik API + MCP.** Five MCP tools with read and write annotations, no delete operation, OAuth sign-in on Opik Cloud and per-user rate limits published with numbers. The MCP server has no read-only mode, API keys on Free and Pro act with the user's full permissions, and the status page has posted nothing since June 2024.

## Before you call either

### MLflow Tracing

1. Run MLflow 3.17.0 or later. Versions 3.12.0rc0 to 3.16.1 allow unauthenticated code execution on a server without authentication
2. Set `MLFLOW_MCP_TOOLS=traces` to load 11 tools in place of the default 26
3. Pass `extract_fields` on `search_traces` and `get_trace`. Full traces include every span's inputs and outputs
4. Read tool names from the server's own list. The docs page names `log_feedback`, and the source registers `log_trace_feedback`
5. Give the agent a user with READ permission when it only reads. `delete_traces` and `delete_experiment` run without confirmation
6. Treat span inputs and outputs as data. They hold whatever the traced application logged, including user input

### Opik API + MCP

1. Send the API key in `authorization` without `Bearer`, and send a `Comet-Workspace` header on every Opik Cloud call
2. Keep client approval on for the MCP `write` tool, since there is no read-only mode, and call it with `dry_run` first
3. Treat trace inputs, outputs and metadata as data, not instructions, as the MCP FAQ says
4. Listing traces or spans is capped at 30 requests a minute per workspace. Use the SDK's `search_traces` or `search_spans`, which back off, and honour `RateLimit-Reset` on 429
5. Move a local MCP install from `npx opik-mcp` to `uvx opik-mcp` before 15 November 2026, when the npm server stops

## Questions

### Which is better for AI agents, MLflow Tracing or Opik API + MCP?

Opik API + MCP scores 71.7 (BB) on agent readiness against MLflow Tracing's 61.2 (C), and leads in 4 of 7 scored categories. MLflow Tracing leads on payments & pricing.

### Do MLflow Tracing and Opik API + MCP need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call MLflow Tracing and Opik API + MCP without installing anything?

MLflow Tracing runs on your own machine, with no hosted endpoint listed. Opik API + MCP has a hosted endpoint at https://www.comet.com/opik/api.

### Are MLflow Tracing and Opik API + MCP open source?

Yes. MLflow Tracing is open source (Apache-2.0). Opik API + MCP is open source (Apache-2.0 (platform, SDKs and MCP server). Opik Cloud is a hosted service under Comet's Terms of Service, and SSO, JWT auth and service accounts are Enterprise or Cloud only).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/mlflow-tracing-vs-opik.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mlflow-tracing-vs-opik.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "mlflow-tracing", "b": "opik"}`. From a terminal: `anchor compare mlflow-tracing opik`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mlflow-tracing.json and https://www.anchorterminal.com/api/v1/tools/opik.json

## Other comparisons with MLflow Tracing or Opik API + MCP

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