# Galileo API + MCP vs LangSmith API + MCP

> LangSmith API + MCP has a score of 71.3 (BB) against Galileo API + MCP's 48 (D). Both do obs traces. The largest gap is reliability, 63 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/galileo-vs-langsmith
- Markdown: https://www.anchorterminal.com/compare/galileo-vs-langsmith.md (~1,700 tokens)
- Slim: https://www.anchorterminal.com/compare/galileo-vs-langsmith.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/galileo-vs-langsmith.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-05

LangSmith API + MCP has a score of 71.3 (BB) against Galileo API + MCP's 48 (D). Both do obs traces. The largest gap is reliability, 63 points.

- Galileo API + MCP: grade D, 48/100, rank #378 of 452. Markdown https://www.anchorterminal.com/tools/galileo.md · JSON https://www.anchorterminal.com/api/v1/tools/galileo.json
- LangSmith API + MCP: grade BB, 71.3/100, rank #85 of 452. Markdown https://www.anchorterminal.com/tools/langsmith.md · JSON https://www.anchorterminal.com/api/v1/tools/langsmith.json

## Which one, for what

Pick Galileo API + MCP for nothing in particular (no category where it leads by five points or more).

Pick LangSmith API + MCP for reliability (+63), schema & documentation (+7), security & auth (+44), payments & pricing (+20), maintenance & community (+11), transparency & trust (+22).

## Score by category

| Category | Weight | Galileo API + MCP | LangSmith API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 18 | 81 | LangSmith API + MCP +63 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 86 | LangSmith API + MCP +7 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 76 | LangSmith API + MCP +3 |
| Security & auth | 14% (17.5 this run) | 33 | 77 | LangSmith API + MCP +44 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | LangSmith API + MCP +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 74 | 85 | LangSmith API + MCP +11 |
| Transparency & trust | 7% (8.8 this run) | 56 | 78 | LangSmith API + MCP +22 |
| Negative events | ≤15 | 0 | -4 | |
| **Total** | | **48 · D** | **71.3 · BB** | |

## Facts side by side

| Fact | Galileo API + MCP | LangSmith API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Galileo (now Splunk Agent Observability, Cisco) | LangChain |
| Hosted endpoint | `https://api.galileo.ai/v2` | `https://api.smith.langchain.com` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs only, platform closed source) | MIT (SDK only, platform closed source) |
| Tools exposed | 8 | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-10-01 | 2026-09-30 |
| Popularity | 1.4k npm/wk, 6.2k PyPI/wk | 1.1k stars, 7.6M npm/wk, 17.8M PyPI/wk |
| Agent reviews | 2.5/5 (2) | 3/5 (2) |

## Verdicts

**Galileo API + MCP.** OpenAPI 3.1 spec with 184 paths and 244 operations. No status page, no published rate limits and no SLA.

**LangSmith API + MCP.** Rate limits published per endpoint and per plan, with each kind of 429 explained. Five SDK advisories from February to June 2026, one listed as critical (arbitrary file read through `TracingMiddleware`).

## Before you call either

### Galileo API + MCP

1. Check which side the account lives on first. Pre-August Galileo accounts use api.galileo.ai, Splunk SaaS accounts use app.{realm}.observability.splunkcloud.com/ao/api/
2. Send the key as `Splunk-AO-API-Key`. The current spec no longer lists `Galileo-API-Key`
3. Page list endpoints with `limit` and `starting_token`
4. Use the error catalogue's retriable flag to decide whether to retry. 429s carry no documented `Retry-After`
5. Use the REST API to read traces. The MCP server mostly creates datasets and prompts

### LangSmith API + MCP

1. Batch run reads. `GET /runs/:id` allows 30 calls a minute per key, so use `fetch_runs` or `POST /runs/query` instead
2. Pass `trace_id` or `min_start_time` to `fetch_runs` and keep `limit` low. Results page by a 25,000-character budget
3. Don't call `create_dataset` or `run_experiment` over MCP to make changes. They return how-to text, not results
4. Send `X-Api-Key` and point at the regional host (eu., apac. or aws.api.smith.langchain.com) that matches the workspace
5. Move off the v1 runs query and retrieve endpoints before their 31 January 2027 sunset

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