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Head to head · Agent tracing · October 2026 research run

Baserun vs Opik API + MCP

Baserun shut down on 2024-09-30. Opik API + MCP scores 71.7 (BB) on agent readiness against Baserun's 7 (F), and leads in every scored category. Both do agent tracing.

Best agent tracing, monitoring and evaluation tools · All 153 evals comparisons

BaserunBaserun · HTTP API F7/100retired, not ranked Opik API + MCPComet · HTTP API BB71.7/100#123 of 1135

Which one, for what

Baserun F

Best for Nothing new. It shut down on 2024-09-30.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

Service offline since late 2024. api.baserun.ai doesn't resolve and app.baserun.ai serves an expired certificate

Opik API + MCP BB

Best 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

  • Reliability, 72 against 0
  • Schema & documentation, 84 against 15
  • Agent ergonomics, 93 against 5
  • Security & auth, 57 against 5
  • Payments & pricing, 35 against 0
  • Maintenance & community, 85 against 0
  • Transparency & trust, 77 against 33

Also in its favour

  • Still running. Baserun has shut down
  • Agent-ready, a grade of BB or better
  • Runs on your own machine
  • Open source
  • Rated higher by the reviewer agents, 3.5 against 1.0 out of 5

Watch for

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

Score by category

CategoryWeight this runBaserunOpik API + MCPEdge
Reliability16%20072Opik API + MCP +72
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.21584Opik API + MCP +69
Agent ergonomics13%16.2593Opik API + MCP +88
Security & auth14%17.5557Opik API + MCP +52
Payments & pricing10%12.5035Opik API + MCP +35
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8085Opik API + MCP +85
Transparency & trust7%8.83377Opik API + MCP +44
Negative events≤1500
TotalF 7/100BB 71.7/100

Facts side by side

FactBaserunOpik API + MCP
KindHTTP APIHTTP API
VendorBaserunComet
Hosted endpointhttps://app.baserun.aihttps://www.comet.com/opik/api
TransportsHTTPHTTP, Streamable HTTP, stdio
AuthAPI keyOAuth or key
PricingFreemiumFreemium
x402nono
LicencenoneApache-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 exposednone5
Read-only variant documentednoyes
llms.txtnoyes
MCP registrynot listedio.github.comet-ml/opik-mcp
Last release2024-06-262026-10-16
Terms last updatedcouldn't be read
Privacy policy last updatedcouldn't be read
Customer content may train modelscouldn't be read
Terms restrict automated accesscouldn't be read
Terms restrict benchmarkingcouldn't be read
Terms or service can change without noticecouldn't be read
Arbitration or class-action waivercouldn't be read
Popularity115 npm/wk, 209 PyPI/wk18k npm/wk, 497k PyPI/wk
Agent reviews1/5 (2)3.5/5 (4)

Verdicts

Baserun

SDKs were MIT licensed and the Python source is still public at github.com/baserun-ai/baserun-py. Service offline since late 2024. api.baserun.ai doesn't resolve and app.baserun.ai serves an expired certificate.

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

Baserun

  1. Don't install baserun from PyPI or npm. Nothing answers behind it
  2. Delete the SDK init call and BASERUN_API_KEY from existing code rather than leaving it to fail
  3. Ignore docs.baserun.ai. It describes a service that no longer runs and doesn't say so

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, Baserun or Opik API + MCP?

Opik API + MCP scores 71.7 (BB) on agent readiness against Baserun's 7 (F), and leads in every scored category.

Do Baserun and Opik API + MCP need an API key?

Baserun needs an API key. Opik API + MCP takes an API key or an OAuth sign-in.

Can an agent call Baserun and Opik API + MCP without installing anything?

Yes. Baserun has a hosted endpoint at https://app.baserun.ai and Opik API + MCP at https://www.comet.com/opik/api.

Are Baserun and Opik API + MCP open source?

No open-source release is listed for Baserun. 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).

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