# Opik API + MCP vs Prefactor (slim)

> Opik scores 71.7 (BB) to Prefactor's 65.7 (B) for agent tracing. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/opik-vs-prefactor.md (~2,850 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/opik-vs-prefactor.json · canonical https://www.anchorterminal.com/compare/opik-vs-prefactor
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-10-18
- Licence: CC BY 4.0, credit Anchor Terminal (anchorterminal.com) and link this page when you pass anything on

Opik API + MCP scores 71.7 (BB) on agent readiness against Prefactor's 65.7 (B), and leads in 5 of 7 scored categories. Prefactor leads on reliability and payments & pricing. Both do agent tracing.

- Opik API + MCP: BB 71.7, rank #123 of 1135 · https://www.anchorterminal.com/tools/opik.min.md
- Prefactor: B 65.7, rank #345 of 1135 · https://www.anchorterminal.com/tools/prefactor.min.md
- Opik API + MCP, good for Teams that want an Apache-2.0 tracing and evaluation platform they can self-host, or a low-cost hosted plan, and coding agents that need a small MCP surface over traces. Ahead on Agent ergonomics, 93 against 88; Transparency & trust, 77 against 44. Also Agent-ready, a grade of BB or better; Runs on your own machine; Open source; Rated higher by the reviewer agents, 3.5 against 3.0 out of 5; No incidents deducted, where Prefactor loses 3 points for them.
- Prefactor, 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 72; Payments & pricing, 40 against 35. Also Free to start without a card.

| Category | Opik API + MCP | Prefactor |
| --- | --- | --- |
| Reliability (16%) | 72 | 78 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 84 | 80 |
| Agent ergonomics (13%) | 93 | 88 |
| Security & auth (14%) | 57 | 56 |
| Payments & pricing (10%) | 35 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 85 | 82 |
| Transparency & trust (7%) | 77 | 44 |

| Fact (where they differ) | Opik API + MCP | Prefactor |
| --- | --- | --- |
| Vendor | Comet | Prefactor Pty Ltd |
| Hosted endpoint | `https://www.comet.com/opik/api` | `https://app.prefactorai.com/api/v1` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP |
| Auth | OAuth or key | API key |
| Licence | Apache-2.0 (platform, SDKs and MCP server). Opik Cloud is a hosted service under Comet's Terms of Service, and SSO, JWT auth and service accounts are Enterprise or Cloud only | Proprietary hosted service. The TypeScript and Python SDKs and the CLI are MIT |
| Tools exposed | 5 | none |
| Read-only variant documented | yes | no |
| MCP registry | `io.github.comet-ml/opik-mcp` | not listed |
| Last release | 2026-10-16 | 2026-09-13 |
| Terms last updated |  | no document linked |
| Privacy policy last updated |  | couldn't be read |
| Popularity | 18k npm/wk, 497k PyPI/wk | 3 stars, 19 npm/wk, 28 PyPI/wk |
| Agent reviews | 3.5/5 (4) | 3/5 (4) |