# Galileo API + MCP vs Prefactor

> Prefactor scores 65.6 (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 transparency & trust. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/galileo-vs-prefactor
- Markdown: https://www.anchorterminal.com/compare/galileo-vs-prefactor.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/galileo-vs-prefactor.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/galileo-vs-prefactor.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: 2026-10-08

Prefactor scores 65.6 (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 transparency & trust. Both do obs traces.

- Galileo API + MCP: grade D, 47.7/100, rank #630 of 722. Markdown https://www.anchorterminal.com/tools/galileo.md · JSON https://www.anchorterminal.com/api/v1/tools/galileo.json
- Prefactor: grade B, 65.6/100, rank #253 of 722. Markdown https://www.anchorterminal.com/tools/prefactor.md · JSON https://www.anchorterminal.com/api/v1/tools/prefactor.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:
- Transparency & trust, 53 against 42

Also in its favour:
- No incidents deducted, where Prefactor loses 3 points for them

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

### Prefactor (B)

Good for: A team that wants an auditable record of agent runs with declared data-risk labels, quality payloads from its own evaluations and a remote stop signal.

Ahead on:
- Reliability, 78 against 18
- Agent ergonomics, 88 against 73
- Security & auth, 56 against 33
- Payments & pricing, 40 against 20
- Maintenance & community, 82 against 74

Also in its favour:
- Free to start without a card

Watch for: The pricing page lists hold, approve or block and PII detection on every plan, while the docs say a risk threshold blocks nothing and that Prefactor does not detect sensitive data


## Score by category

| Category | Weight | Galileo API + MCP | Prefactor | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 18 | 78 | Prefactor +60 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 79 | 80 | Prefactor +1 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 88 | Prefactor +15 |
| Security & auth | 14% (17.5 this run) | 33 | 56 | Prefactor +23 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Prefactor +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 74 | 82 | Prefactor +8 |
| Transparency & trust | 7% (8.8 this run) | 53 | 42 | Galileo API + MCP +11 |
| Negative events | ≤15 | 0 | -3 | |
| **Total** | | **47.7 · D** | **65.6 · B** | |

## Facts side by side

| Fact | Galileo API + MCP | Prefactor |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Galileo (now Splunk Agent Observability, Cisco) | Prefactor Pty Ltd |
| Hosted endpoint | `https://api.galileo.ai/v2` | `https://app.prefactorai.com/api/v1` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs only, platform closed source) | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT |
| Tools exposed | 8 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-01 | 2026-09-13 |
| Terms last updated | no date given | no document linked |
| Privacy policy last updated | 2024-11-01 | couldn't be read |
| Customer content may train models | yes |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 1.4k npm/wk, 6.2k PyPI/wk | 3 stars, 19 npm/wk, 28 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.

**Prefactor.** The public OpenAPI document lists 157 operations, each accepting an idempotency key, and tokens can be read-only or bound to one agent deployment. The pricing and security pages describe approval, blocking and PII detection that the documentation says the product does not do, and the only published terms cover the website.

## 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

### Prefactor

1. Send requests to `https://app.prefactorai.com/api/v1` with `Authorization: Bearer <token>`. The API host is not on the `prefactor.tech` or `prefactor.ai` domains
2. Ask for a deployment-scoped token, or an account token created with `role` set to `read_only`, since the default role is `full_access` with a two-year expiry
3. Pass `redacted: true` on span list and detail queries, because the API returns marked sensitive values unless asked otherwise
4. On 429 wait for `retry_after_ms`. Limits use one-minute windows and the SDKs' default retries ignore the server's hint
5. Treat terminate as a request. Check the control signal on span responses or poll the instance, because Prefactor does not stop the process

## Questions

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

Prefactor scores 65.6 (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 transparency & trust.

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

Both need an API key.

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

Yes. Galileo API + MCP has a hosted endpoint at https://api.galileo.ai/v2 and Prefactor at https://app.prefactorai.com/api/v1.


## For agents

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

## Other comparisons with Galileo API + MCP or Prefactor

- [Arize Phoenix vs Galileo API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.md)
- [Arize Phoenix vs Prefactor](https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor.md)
- [Baserun vs Galileo API + MCP](https://www.anchorterminal.com/compare/baserun-vs-galileo.md)
- [Baserun vs Prefactor](https://www.anchorterminal.com/compare/baserun-vs-prefactor.md)
- [Braintrust API + MCP vs Galileo API + MCP](https://www.anchorterminal.com/compare/braintrust-vs-galileo.md)
- [Braintrust API + MCP vs Prefactor](https://www.anchorterminal.com/compare/braintrust-vs-prefactor.md)
- [Galileo API + MCP vs Helicone AI Gateway + MCP](https://www.anchorterminal.com/compare/galileo-vs-helicone.md)
- [Galileo API + MCP vs HoneyHive](https://www.anchorterminal.com/compare/galileo-vs-honeyhive.md)
- [Galileo API + MCP vs Laminar API + MCP](https://www.anchorterminal.com/compare/galileo-vs-laminar.md)
- [Galileo API + MCP vs Langfuse API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langfuse.md)
- [Galileo API + MCP vs LangSmith API + MCP](https://www.anchorterminal.com/compare/galileo-vs-langsmith.md)
- [Galileo API + MCP vs Respan API + MCP](https://www.anchorterminal.com/compare/galileo-vs-respan.md)
- [Helicone AI Gateway + MCP vs Prefactor](https://www.anchorterminal.com/compare/helicone-vs-prefactor.md)
- [HoneyHive vs Prefactor](https://www.anchorterminal.com/compare/honeyhive-vs-prefactor.md)
- [Laminar API + MCP vs Prefactor](https://www.anchorterminal.com/compare/laminar-vs-prefactor.md)
- [Langfuse API + MCP vs Prefactor](https://www.anchorterminal.com/compare/langfuse-vs-prefactor.md)
- [LangSmith API + MCP vs Prefactor](https://www.anchorterminal.com/compare/langsmith-vs-prefactor.md)
- [Prefactor vs Respan API + MCP](https://www.anchorterminal.com/compare/prefactor-vs-respan.md)