# Galileo API + MCP vs LangWatch

> LangWatch scores 65.5 (B) on agent readiness against Galileo API + MCP's 47.7 (D), and leads in 6 of 7 scored categories. Galileo API + MCP leads on agent ergonomics. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/galileo-vs-langwatch
- Markdown: https://www.anchorterminal.com/compare/galileo-vs-langwatch.md (~2,450 tokens)
- Slim: https://www.anchorterminal.com/compare/galileo-vs-langwatch.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/galileo-vs-langwatch.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: 2026-10-09

LangWatch scores 65.5 (B) on agent readiness against Galileo API + MCP's 47.7 (D), and leads in 6 of 7 scored categories. Galileo API + MCP leads on agent ergonomics. Both do obs traces.

- Galileo API + MCP: grade D, 47.7/100, rank #736 of 842. Markdown https://www.anchorterminal.com/tools/galileo.md · JSON https://www.anchorterminal.com/api/v1/tools/galileo.json
- LangWatch: grade B, 65.5/100, rank #291 of 842. Markdown https://www.anchorterminal.com/tools/langwatch.md · JSON https://www.anchorterminal.com/api/v1/tools/langwatch.json

## Which one, for what

### Galileo API + MCP (D)

Good for: Existing Galileo customers and teams already on Splunk Observability Cloud who want eval metrics and guardrails next to their infrastructure monitoring.

Ahead on:
- Agent ergonomics, 73 against 67

Watch for: No status page, no published rate limits and no SLA

### LangWatch (B)

Good for: Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.

Ahead on:
- Reliability, 53 against 18
- Schema & documentation, 87 against 79
- Security & auth, 71 against 33
- Payments & pricing, 40 against 20
- Maintenance & community, 90 against 74
- Transparency & trust, 75 against 53

Also in its favour:
- Runs on your own machine
- Free to start without a card
- Open source

Watch for: The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source


## Score by category

| Category | Weight | Galileo API + MCP | LangWatch | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 18 | 53 | LangWatch +35 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 87 | LangWatch +8 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 67 | Galileo API + MCP +6 |
| Security & auth | 14% (17.5 this run) | 33 | 71 | LangWatch +38 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | LangWatch +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 74 | 90 | LangWatch +16 |
| Transparency & trust | 7% (8.8 this run) | 53 | 75 | LangWatch +22 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **47.7 · D** | **65.5 · B** | |

## Facts side by side

| Fact | Galileo API + MCP | LangWatch |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Galileo (now Splunk Agent Observability, Cisco) | Reasoning Engine B.V. (LangWatch) |
| Hosted endpoint | `https://api.galileo.ai/v2` | `https://app.langwatch.ai` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP, SSE (legacy), stdio |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs only, platform closed source) | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |
| Tools exposed | 8 | 101 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-01 | 2026-10-02 |
| Terms last updated | no date given | 2026-09-22 |
| Privacy policy last updated | 2024-11-01 | 2026-09-29 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 1.4k npm/wk, 6.2k PyPI/wk | 4.9k stars, 50k npm/wk, 87k PyPI/wk |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

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

**LangWatch.** API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation.

## 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

### LangWatch

1. Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do
2. Set both `LANGWATCH_API_KEY` and `LANGWATCH_PROJECT_ID` for the MCP server unless the key reaches only one project
3. Call `discover_schema` before `search_traces` or `get_analytics`, and keep the default `digest` format. `json` returns the full raw trace
4. Allowlist MCP tools in the client. All 101 load by default, among them `platform_create_api_key` and the delete tools
5. Follow `next_cursor` until it is null on list endpoints. A full page does not mean more rows exist

## Questions

### Which is better for AI agents, Galileo API + MCP or LangWatch?

LangWatch scores 65.5 (B) on agent readiness against Galileo API + MCP's 47.7 (D), and leads in 6 of 7 scored categories. Galileo API + MCP leads on agent ergonomics.

### Do Galileo API + MCP and LangWatch need an API key?

Galileo API + MCP needs an API key. LangWatch takes an API key or an OAuth sign-in.

### Can an agent call Galileo API + MCP and LangWatch without installing anything?

Yes. Galileo API + MCP has a hosted endpoint at https://api.galileo.ai/v2 and LangWatch at https://app.langwatch.ai.

### Are Galileo API + MCP and LangWatch open source?

No open-source release is listed for Galileo API + MCP. LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/galileo-vs-langwatch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/galileo-vs-langwatch.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "galileo", "b": "langwatch"}`. From a terminal: `anchor compare galileo langwatch`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/galileo.json and https://www.anchorterminal.com/api/v1/tools/langwatch.json

## Other comparisons with Galileo API + MCP or LangWatch

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- [Arize Phoenix vs LangWatch](https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.md)
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- [LangWatch vs W&B Weave](https://www.anchorterminal.com/compare/langwatch-vs-wandb-weave.md)