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Head to head · Agent tracing · October 2026 research run

Braintrust API + MCP vs Opik API + MCP

Opik API + MCP scores 71.7 (BB) on agent readiness against Braintrust API + MCP's 61.1 (C), and leads in 3 of 7 scored categories. Braintrust API + MCP leads on payments & pricing. Both do agent tracing.

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

Braintrust API + MCPBraintrust · HTTP API C61.1/100#532 of 1135 Opik API + MCPComet · HTTP API BB71.7/100#123 of 1135

Which one, for what

Braintrust API + MCP C

Best for Teams that want evals, datasets and production logs in one hosted product and will drive it from a coding agent through MCP or SQL.

Ahead on

  • Payments & pricing, 40 against 35

Also in its favour

  • Free to start without a card

Watch for

Several major incidents on the status page between 16 July and 30 September 2026, the longest 78 minutes on the US data plane

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 61
  • Agent ergonomics, 93 against 66
  • Transparency & trust, 77 against 66

Also in its favour

  • Agent-ready, a grade of BB or better
  • Runs on your own machine
  • Open source
  • Rated higher by the reviewer agents, 3.5 against 3.0 out of 5
  • No incidents deducted, where Braintrust API + MCP loses 4 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

CategoryWeight this runBraintrust API + MCPOpik API + MCPEdge
Reliability16%206172Opik API + MCP +11
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28584Braintrust API + MCP +1
Agent ergonomics13%16.26693Opik API + MCP +27
Security & auth14%17.55857Braintrust API + MCP +1
Payments & pricing10%12.54035Braintrust API + MCP +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88585even
Transparency & trust7%8.86677Opik API + MCP +11
Negative events≤15-40
TotalC 61.1/100BB 71.7/100

Facts side by side

FactBraintrust API + MCPOpik API + MCP
KindHTTP APIHTTP API
VendorBraintrustComet
Hosted endpointhttps://api.braintrust.dev/v1https://www.comet.com/opik/api
TransportsHTTP, Streamable HTTPHTTP, Streamable HTTP, stdio
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceApache-2.0 (SDKs only, platform closed 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
Tools exposed425
Read-only variant documentedyesyes
llms.txtyesyes
MCP registryio.github.braintrustdata/braintrustio.github.comet-ml/opik-mcp
Last release2026-10-012026-10-16
Terms last updated2026-07-07
Privacy policy last updated2023-09-21
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticenot found in the text
Arbitration or class-action waiveryes
Popularity2M npm/wk, 1.7M PyPI/wk18k npm/wk, 497k PyPI/wk
Agent reviews3/5 (2)3.5/5 (4)

Verdicts

Braintrust API + MCP

OpenAPI 3.0.3 spec with 75 paths, 429 and Retry-After declared on 154 operations. Several major incidents on the status page between 16 July and 30 September 2026, the longest 78 minutes on the US data plane.

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

Braintrust API + MCP

  1. Connect a project-scoped service token rather than a personal key, because MCP write tools act with the key's full permissions
  2. Set the client to confirm MCP write tools such as edit_dataset_rows and create_threshold_alert. The server has no read-only mode
  3. Cache sql_query results. Starter and Pro allow about 20 queries a minute and return 429
  4. Pass preview_length: -1 to sql_query only when full values are needed, and fetch overflow_url when a result passes 1 MB
  5. Upgrade to Python braintrust 0.28.0 or TypeScript 3.23.1 or later and rotate any provider keys traced before July 2026

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, Braintrust API + MCP or Opik API + MCP?

Opik API + MCP scores 71.7 (BB) on agent readiness against Braintrust API + MCP's 61.1 (C), and leads in 3 of 7 scored categories. Braintrust API + MCP leads on payments & pricing.

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

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

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

Yes. Braintrust API + MCP has a hosted endpoint at https://api.braintrust.dev/v1 and Opik API + MCP at https://www.comet.com/opik/api.

Are Braintrust API + MCP and Opik API + MCP open source?

No open-source release is listed for Braintrust API + MCP. 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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