# Laminar API + MCP vs LangSmith API + MCP

> LangSmith API + MCP has a score of 71.3 (BB) against Laminar API + MCP's 57 (C). Both do obs traces. The largest gap is security & auth, 32 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/laminar-vs-langsmith
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- Slim: https://www.anchorterminal.com/compare/laminar-vs-langsmith.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/laminar-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 Laminar API + MCP's 57 (C). Both do obs traces. The largest gap is security & auth, 32 points.

- Laminar API + MCP: grade C, 57/100, rank #298 of 452. Markdown https://www.anchorterminal.com/tools/laminar.md · JSON https://www.anchorterminal.com/api/v1/tools/laminar.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 Laminar API + MCP for nothing in particular (no category where it leads by five points or more).

Pick LangSmith API + MCP for reliability (+31), security & auth (+32), payments & pricing (+10), transparency & trust (+12).

## Score by category

| Category | Weight | Laminar API + MCP | LangSmith API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 50 | 81 | LangSmith API + MCP +31 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 86 | Laminar API + MCP +2 |
| Agent ergonomics | 13% (16.2 this run) | 80 | 76 | Laminar API + MCP +4 |
| Security & auth | 14% (17.5 this run) | 45 | 77 | LangSmith API + MCP +32 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | LangSmith API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 85 | LangSmith API + MCP +2 |
| Transparency & trust | 7% (8.8 this run) | 66 | 78 | LangSmith API + MCP +12 |
| Negative events | ≤15 | -5 | -4 | |
| **Total** | | **57 · C** | **71.3 · BB** | |

## Facts side by side

| Fact | Laminar API + MCP | LangSmith API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Laminar (LMNR AI) | LangChain |
| Hosted endpoint | `https://api.lmnr.ai/v1` | `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 | MIT (SDK only, platform closed source) |
| Tools exposed | 3 | 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 | yes | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-23 | 2026-09-30 |
| Popularity | 3.3k stars, 80k npm/wk, 1.7M PyPI/wk | 1.1k stars, 7.6M npm/wk, 17.8M PyPI/wk |
| Agent reviews | 3.5/5 (2) | 3/5 (2) |

## Verdicts

**Laminar API + MCP.** Browser session recordings can be matched to agent traces. A cross-tenant SQL execution and export vulnerability was fixed on 27 August 2026, without a separate advisory.

**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

### Laminar API + MCP

1. Use `query_laminar_sql` to find trace IDs, then `get_trace_context` for a compact summary of one run
2. Always add a time range and `LIMIT` to SQL. Server caps on time, memory and result size reject wide scans
3. On 429 from the SQL API, back off. The per-project limit isn't published
4. Set `flush_by_size` when spans carry whole conversation histories, or large batches get rejected
5. Keep the project API key in a header, not in the URL

### 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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