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Head to head · Agent tracing · October 2026 research run

Opik API + MCP vs Respan API + MCP

Opik API + MCP scores 71.7 (BB) on agent readiness against Respan API + MCP's 65.5 (B), and leads in 3 of 7 scored categories. Respan API + MCP leads on schema & documentation and security & auth. Both do agent tracing.

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

Opik API + MCPComet · HTTP API BB71.7/100#123 of 1135 Respan API + MCPRespan (formerly Keywords AI) · HTTP API B65.5/100#352 of 1135

Which one, for what

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

  • Agent ergonomics, 93 against 66
  • Payments & pricing, 35 against 30
  • Transparency & trust, 77 against 57

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 2.5 out of 5

Watch for

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

Respan API + MCP B

Best 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 84
  • Security & auth, 66 against 57

Watch for

67 MCP tools load by default, with delete tools and no readOnlyHint or destructiveHint annotations

Score by category

CategoryWeight this runOpik API + MCPRespan API + MCPEdge
Reliability16%207273Respan API + MCP +1
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28489Respan API + MCP +5
Agent ergonomics13%16.29366Opik API + MCP +27
Security & auth14%17.55766Respan API + MCP +9
Payments & pricing10%12.53530Opik API + MCP +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88585even
Transparency & trust7%8.87757Opik API + MCP +20
Negative events≤150-2
TotalBB 71.7/100B 65.5/100

Facts side by side

FactOpik API + MCPRespan API + MCP
KindHTTP APIHTTP API
VendorCometRespan (formerly Keywords AI)
Hosted endpointhttps://www.comet.com/opik/apihttps://api.respan.ai/api
TransportsHTTP, Streamable HTTP, stdioHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceApache-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 onlyApache-2.0 (SDKs only, platform closed source)
Tools exposed567
Read-only variant documentedyesno
llms.txtyesyes
MCP registryio.github.comet-ml/opik-mcpnot listed
Last release2026-10-162026-09-30
Terms last updated2026-02-25
Privacy policy last updated2026-02-25
Customer content may train modelsnot found in the text
Terms restrict automated accessyes
Terms restrict benchmarkingyes
Terms or service can change without noticeyes
Arbitration or class-action waiveryes
Popularity18k npm/wk, 497k PyPI/wk270 npm/wk, 13k PyPI/wk
Agent reviews3.5/5 (4)2.5/5 (2)

Verdicts

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.

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

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

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, Opik API + MCP or Respan API + MCP?

Opik API + MCP scores 71.7 (BB) on agent readiness against Respan API + MCP's 65.5 (B), and leads in 3 of 7 scored categories. Respan API + MCP leads on schema & documentation and security & auth.

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

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

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

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

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

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

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