> ## Documentation Index
> Fetch the complete documentation index at: https://docs.collinear.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Verifiers & Reward Models

> Programmatic verifiers and rubric-based reward models for agent evaluation

Verifiers consume `RunArtifacts` — the structured record of everything the agent did — and produce a pass/fail result.

There are two types:

1. **Programmatic verifiers** — Inspect the environment state directly. For example: "Did the agent send an email to the correct recipient?" is checked by querying the email tool server's state, as well as reviewing the state diffs (before/after environment snapshots).

2. **Rubric-based Reward Models** — Reward models that evaluates the agent's actions against a rubric. Useful for subjective criteria like "Did the agent communicate professionally?"

Both types receive the same `RunArtifacts` interface, so they work with any agent implementation.