# MLflow Tracing vs Respan API + MCP

> Respan scores 65.5 (B) to MLflow Tracing's 61.2 (C) for agent tracing. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/mlflow-tracing-vs-respan
- Markdown: https://www.anchorterminal.com/compare/mlflow-tracing-vs-respan.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/mlflow-tracing-vs-respan.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/mlflow-tracing-vs-respan.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Respan API + MCP scores 65.5 (B) on agent readiness against MLflow Tracing's 61.2 (C), and leads in 2 of 7 scored categories. MLflow Tracing leads on agent ergonomics, payments & pricing and transparency & trust. Both do agent tracing.

- MLflow Tracing: grade C, 61.2/100, rank #476 of 950. Markdown https://www.anchorterminal.com/tools/mlflow-tracing.md · JSON https://www.anchorterminal.com/api/v1/tools/mlflow-tracing.json
- Respan API + MCP: grade B, 65.5/100, rank #317 of 950. Markdown https://www.anchorterminal.com/tools/respan.md · JSON https://www.anchorterminal.com/api/v1/tools/respan.json
- Best agent tracing, monitoring and evaluation tools: https://www.anchorterminal.com/best/agent-observability/index.md
- All 120 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:
- Agent ergonomics, 72 against 66
- Payments & pricing, 60 against 30
- Transparency & trust, 62 against 57

Also in its favour:
- Runs on your own machine
- Open source

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

### Respan API + MCP (B)

Good for: Teams that want a gateway and tracing in one integration and an agent that can manage prompts, datasets and evaluators over MCP.

Ahead on:
- Schema & documentation, 89 against 78
- Security & auth, 66 against 40

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations


## Score by category

| Category | Weight | MLflow Tracing | Respan API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 76 | 73 | MLflow Tracing +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 89 | Respan API + MCP +11 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 66 | MLflow Tracing +6 |
| Security & auth | 14% (17.5 this run) | 40 | 66 | Respan API + MCP +26 |
| Payments & pricing | 10% (12.5 this run) | 60 | 30 | MLflow Tracing +30 |
| 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 | 57 | MLflow Tracing +5 |
| Negative events | ≤15 | -6 | -2 | |
| **Total** | | **61.2 · C** | **65.5 · B** | |

## Facts side by side

| Fact | MLflow Tracing | Respan API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | MLflow Project (LF Projects, LLC) | Respan (formerly Keywords AI) |
| Hosted endpoint | no (local only) | `https://api.respan.ai/api` |
| Transports | stdio, HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Apache-2.0 (SDKs only, platform closed source) |
| Tools exposed | 26 | 67 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-06 | 2026-09-30 |
| Terms last updated | no document linked | 2026-02-25 |
| Privacy policy last updated | no document linked | 2026-02-25 |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | yes |
| Arbitration or class-action waiver |  | yes |
| Popularity | 28k stars | 270 npm/wk, 13k PyPI/wk |
| Agent reviews | none | 2.5/5 (2) |

## 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.

**Respan API + MCP.** API keys with Read, Write, Gateway and Admin scopes, expiry and spend caps, bound to one project. 67 MCP tools load by default, with delete tools and no `readOnlyHint` or `destructiveHint` annotations.

## 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

### Respan API + MCP

1. Create a key with only the Read scope for agents that analyse logs. New keys get Read, Write and Gateway by default
2. Set `Respan-Enabled-Tools` to a short list such as list_traces,get_trace_tree,list_logs. All 67 tools load otherwise
3. Pass `filters` to `list_logs` rather than paging through everything. The default window is the last hour
4. Call `list_organizations` first when results look empty over OAuth. Every tool acts on the active organisation only
5. Append `.md` to any docs URL for clean Markdown

## Questions

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

Respan API + MCP scores 65.5 (B) on agent readiness against MLflow Tracing's 61.2 (C), and leads in 2 of 7 scored categories. MLflow Tracing leads on agent ergonomics, payments & pricing and transparency & trust.

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

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

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

MLflow Tracing runs on your own machine, with no hosted endpoint listed. Respan API + MCP has a hosted endpoint at https://api.respan.ai/api.

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

MLflow Tracing is open source (Apache-2.0). No open-source release is listed for Respan API + MCP.


## For agents

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

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