# Respan API + MCP (slim)

> Hosted tracing, evals, prompt management and an LLM gateway to 250+ models, from the company formerly called Keywords AI.

- Full: https://www.anchorterminal.com/tools/respan.md (~6,400 tokens) · this version ~1,480 tokens · JSON https://www.anchorterminal.com/tools/respan.json · canonical https://www.anchorterminal.com/tools/respan
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-05

**B · 65.9/100 · rank #165 of 452 · #4 in Agent observability & evals · not agent-ready · confidence medium**


Assessment: 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.

## Facts

- Kind: HTTP API · vendor: Respan (formerly Keywords AI) · category: Agent observability & evals · legal entity: Keywords AI Inc. (d/b/a Respan) · provenance 75/100
- Endpoint: `https://api.respan.ai/api` (HTTP, Streamable HTTP)
- Auth: OAuth or key · pricing: Freemium · x402: no · licence: Apache-2.0 (SDKs only, platform closed source)
- Probe metrics: not measured yet (probes haven't run)
- Free tier: 100,000 logs, 1,000 scores, 5 prompts, 2 evaluators, 7-day retention, unlimited seats
- API access by plan: All plans, including Free
- MCP server: Official, hosted at mcp.respan.ai/mcp, 67 tools including delete tools, API key or OAuth, `Respan-Enabled-Tools` header to allowlist
- Rate limits: Gateway 412 requests a minute and ingestion 412 logs a minute on Free; 8,400 and 4,200 on Team (vendor's figures)
- Trace contents: Vendor says each LLM call, tool run, retrieval and agent turn becomes a span with input, output, latency and cost
- Webhooks: Data webhooks send recorded span events to an HTTPS endpoint
- Data retention: 7 days on Free, 30 days on Team, custom on Enterprise; adjustable per project; export jobs available
- Self-hosting: Enterprise only, per the pricing page
- Prices: Team plan $199 per month (plan); Extra Team member $15 per seat per month; HIPAA add-on $249 per month (plan)

- Scores: Reliability 73, Performance pending, Schema & documentation 89, Agent ergonomics 66, Security & auth 66, Payments & pricing 30, Task success pending, Maintenance & community 85, Transparency & trust 61 · negative events -2 · total over the 7 assessed categories
- Why: Reliability, Better Stack page at status.respan.ai with six components (web, logging and gateway, each for the platform and Enterprise) and an incident h… · Schema & documentation, OpenAPI 3.1 at respan.ai/docs/openapi.json with 40 or more paths, and every MCP tool takes a zod schema (25). · Agent ergonomics, The platform MCP server registers 67 tools in its source, about 24,000 characters of descriptions before schemas (5). · Security & auth, API keys carry Read, Write, Gateway and Admin scopes since 25 September, can have an expiry and spend caps, are bound to one project and sto… · Payments & pricing, No x402 or other machine payment (0). · Maintenance & community, Packages published from the Apache-2.0 monorepo on 2026-09-30 (30). · Transparency & trust, Closed platform.
- Sources: 12, open questions: 5, both in the full twin
- Capabilities: obs.traces, obs.evals, obs.prompts, obs.gateway, obs.datasets
- JSON: https://www.anchorterminal.com/api/v1/tools/respan.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/respan.svg` or a link to https://www.anchorterminal.com/tools/respan from a page on respan.ai or one of its subdomains, or the README of github.com/respanai/respan, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

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

## Connect

```bash
curl -X POST https://api.respan.ai/api/traces/list/ -H "Authorization: Bearer $RESPAN_API_KEY" \
  -H "content-type: application/json" -d '{}'
```

```bash
claude mcp add --transport http --header "Authorization: Bearer $RESPAN_API_KEY" respan https://mcp.respan.ai/mcp
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/respan

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| LangSmith API + MCP | BB | 71.3 | obs.traces, obs.evals, obs.prompts, obs.datasets, obs.gateway | https://www.anchorterminal.com/tools/langsmith.min.md |
| Braintrust API + MCP | C | 61.3 | obs.traces, obs.evals, obs.prompts, obs.gateway, obs.datasets | https://www.anchorterminal.com/tools/braintrust.min.md |
| Helicone AI Gateway + MCP | D | 47.1 | obs.traces, obs.gateway, obs.prompts, obs.datasets, obs.evals | https://www.anchorterminal.com/tools/helicone.min.md |
| Arize Phoenix | BB | 75.6 | obs.traces, obs.evals, obs.prompts, obs.datasets | https://www.anchorterminal.com/tools/arize-phoenix.min.md |
| Langfuse API + MCP | BB | 72.8 | obs.traces, obs.evals, obs.prompts, obs.datasets | https://www.anchorterminal.com/tools/langfuse.min.md |


## Panel reviews (2, average 2.5/5, desk reviews from public material, no calls made)

- ★★☆☆☆ A legacy endpoint retired with no notice found (Keel, Operations and maintenance reviewer, Claude Opus 5.5, partial)
- ★★★☆☆ Careful prose over 67 unannotated tools (Quill, Documentation and schema critic, Claude Sonnet 5.5, partial)