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Flint AI Eval tests agent behavior and reliability at runtime. Configuration lives in ~/.flintai/config.json and defines:
  • What to test - Your running agent’s HTTP endpoint
  • How to test it - Which evaluations to run
  • When to test - Model-evaluation assignments
Configuration is only needed for flintai eval commands. flintai scan uses environment variables instead.

Quick start

Create ~/.flintai/config.json with this minimal configuration:
Then run:
Your agent must be running and accessible at the host URL before testing.

Configuration file format

The config file is a JSON file with five optional top-level sections. Only include sections you need.
Most users only need to define models and attach built-in evaluations via CLI:
Then attach evaluations:

Using environment variables in config

Reference environment variables in config.json using ${VAR_NAME} syntax instead of hardcoding sensitive values:
Security: Never hardcode API keys in config files. Use ${...} references to keep credentials in environment variables or .env files instead.
See Environment variables for the complete list and additional examples.

Models section

The models array defines agents or LLMs you want to test. Each model requires these fields:

Required fields

Optional fields

Supported agent types

All types support temperature, tags, and description as optional fields.

Verify your models


Model evaluations section

The model_evaluations array assigns tests to models. Each assignment links one model to one evaluation.

Required fields

Optional fields


To manage model-evaluation assignments via CLI, see the Commands reference or Examples for practical workflows.

Built-in config and overrides

Flint AI loads two config layers:
  1. Built-in config — Ships with the tool, contains all built-in evaluations, detectors, and message collections
  2. User config — Your ~/.flintai/config.json (or path via --config)
The two are merged, with user entries taking precedence on ID conflicts. You can override any built-in evaluation by defining one with the same ID in your config. At startup, Flint AI shows a breakdown:

Configuration file location

Default location: ~/.flintai/config.json Override with --config:

Browse available evaluations

See Built-in evaluations for the full catalog.

Next steps

Run Evaluations

Execute tests against your configured models

View Results

Analyze evaluation outputs

Environment Variables

Manage API keys and settings