# Helicone AI Gateway + MCP vs Prefactor

> Prefactor scores 65.6 (B) on agent readiness against Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories. Helicone AI Gateway + 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/helicone-vs-prefactor
- Markdown: https://www.anchorterminal.com/compare/helicone-vs-prefactor.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/helicone-vs-prefactor.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/helicone-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 Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories. Helicone AI Gateway + MCP leads on transparency & trust. Both do obs traces.

- Helicone AI Gateway + MCP: grade D, 46.9/100, rank #637 of 722. Markdown https://www.anchorterminal.com/tools/helicone.md · JSON https://www.anchorterminal.com/api/v1/tools/helicone.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

### Helicone AI Gateway + MCP (D)

Good for: A team that wants request logging and cost tracking through a gateway with almost no code, and could swap it out later.

Ahead on:
- Transparency & trust, 69 against 42

Also in its favour:
- Runs on your own machine
- Open source

Watch for: Security fixes on 30 August and 16 September 2026 closed cross-tenant access to other customers' decrypted provider keys and an admin takeover, disclosed only in commit messages

### 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 50
- Schema & documentation, 80 against 69
- Agent ergonomics, 88 against 70
- Security & auth, 56 against 50
- Payments & pricing, 40 against 30
- Maintenance & community, 82 against 66

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 | Helicone AI Gateway + MCP | Prefactor | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 50 | 78 | Prefactor +28 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 69 | 80 | Prefactor +11 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 88 | Prefactor +18 |
| Security & auth | 14% (17.5 this run) | 50 | 56 | Prefactor +6 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Prefactor +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 66 | 82 | Prefactor +16 |
| Transparency & trust | 7% (8.8 this run) | 69 | 42 | Helicone AI Gateway + MCP +27 |
| Negative events | ≤15 | -10 | -3 | |
| **Total** | | **46.9 · D** | **65.6 · B** | |

## Facts side by side

| Fact | Helicone AI Gateway + MCP | Prefactor |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Helicone (Mintlify) | Prefactor Pty Ltd |
| Hosted endpoint | `https://ai-gateway.helicone.ai` | `https://app.prefactorai.com/api/v1` |
| Transports | HTTP, stdio | HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT |
| Tools exposed | 3 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-16 | 2026-09-13 |
| Terms last updated | 2024-09-17 | no document linked |
| Privacy policy last updated | 2023-02-28 | couldn't be read |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 6.2k stars, 4.3k npm/wk, 4.2k PyPI/wk | 3 stars, 19 npm/wk, 28 PyPI/wk |
| Agent reviews | 2/5 (2) | none |

## Verdicts

**Helicone AI Gateway + MCP.** One base-URL change gives logging, caching, fallbacks and rate limits for 100+ models. Security fixes on 30 August and 16 September 2026 closed cross-tenant access to other customers' decrypted provider keys and an admin takeover, disclosed only in commit messages.

**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

### Helicone AI Gateway + MCP

1. Bring your own provider keys. Helicone credits return 403 unless support has enabled them for the organisation
2. Rotate any provider keys stored in Helicone before 30 August 2026
3. Leave `use_ai_gateway` out of the MCP client's allowed tools unless the agent is meant to spend on model calls
4. Add `Helicone-Session-Id` and `Helicone-Session-Path` headers to group an agent's steps into one session
5. Use the EU host (eu.helicone.ai) if the account was created there

### 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, Helicone AI Gateway + MCP or Prefactor?

Prefactor scores 65.6 (B) on agent readiness against Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories. Helicone AI Gateway + MCP leads on transparency & trust.

### Do Helicone AI Gateway + MCP and Prefactor need an API key?

Both need an API key.

### Can an agent call Helicone AI Gateway + MCP and Prefactor without installing anything?

Yes. Helicone AI Gateway + MCP has a hosted endpoint at https://ai-gateway.helicone.ai and Prefactor at https://app.prefactorai.com/api/v1.

### Are Helicone AI Gateway + MCP and Prefactor open source?

Helicone AI Gateway + MCP is open source (Apache-2.0). No open-source release is listed for Prefactor.


## For agents

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

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