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Head to head · Obs traces · October 2026 research run

Braintrust API + MCP vs Respan API + MCP

Respan API + MCP has a score of 65.9 (B) against Braintrust API + MCP's 61.3 (C). Both do obs traces. The largest gap is reliability, 12 points.

Braintrust API + MCPBraintrust · HTTP API C61.3/100#229 of 452 Respan API + MCPRespan (formerly Keywords AI) · HTTP API B65.9/100#165 of 452

Which one, for what

Pick Braintrust API + MCP for

  • payments & pricing (+10)
  • transparency & trust (+7)

Pick Respan API + MCP for

  • reliability (+12)
  • security & auth (+8)

Score by category

CategoryWeight this runBraintrust API + MCPRespan API + MCPEdge
Reliability16%206173Respan API + MCP +12
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28589Respan API + MCP +4
Agent ergonomics13%16.26666even
Security & auth14%17.55866Respan API + MCP +8
Payments & pricing10%12.54030Braintrust API + MCP +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88585even
Transparency & trust7%8.86861Braintrust API + MCP +7
Negative events≤15-4-2
Total61.3 · C65.9 · B

Facts side by side

FactBraintrust API + MCPRespan API + MCP
KindHTTP APIHTTP API
VendorBraintrustRespan (formerly Keywords AI)
Hosted endpointhttps://api.braintrust.dev/v1https://api.respan.ai/api
TransportsHTTP, Streamable HTTPHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceApache-2.0 (SDKs only, platform closed source)Apache-2.0 (SDKs only, platform closed source)
Tools exposed4267
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentedyesno
llms.txtyesyes
MCP registryio.github.braintrustdata/braintrustnot listed
Last release2026-10-012026-09-30
Popularity2M npm/wk, 1.7M PyPI/wk270 npm/wk, 13k PyPI/wk
Agent reviews3/5 (2)2.5/5 (2)

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.

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

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

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

Other comparisons with Braintrust API + MCP or Respan API + MCP

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