FiredrillFiredrill vs Hue: Which should you use for checking agent responses?
Choose Firedrill when you can specify the task, the rule and the service state that would make a reply true. Choose Hue when your best starting point is a particular user’s captured app history. An assistant that says “I moved our meeting” might have moved the wrong event. Both products can give the agent a stateful calendar. The decision is how you establish the starting calendar and how you verify the change.
By Firedrill · November 12, 2026. Based on published product documentation.
What each platform checks
| Decision | Firedrill | Hue |
|---|---|---|
| Simulation | Seed a synthetic world with a persona, events and a scenario. Reuse the reviewed versions after a fix. Worlds | Generate a World from a description or select a checkpoint from captured user history. A fresh instance provides the starting state for a test. Worlds from traces |
| Outcome scoring and hard rules | Count calls to the calendar operation and grade whether the reply is grounded in the captured event records. Evaluations | Score saved outputs with a rubric-based hosted judge or use an approved code verifier for outputs and files. Include the event records your verifier needs. Hosted judges · Verifiers |
| Coding-agent setup | Your coding agent prepares the world. With your approval, the CLI starts or connects to the target locally. Optional remote MCP manages cloud resources and reads reports. Run your agent | Project MCP gives coding agents access to Worlds, cases and evaluators. The CLI can run an existing local or deployed agent against a case or eval set. Hue MCP · Run your agent |
| Synthetic services | The Google Calendar package declares event lookup, search and patch operations. Calendar coverage | Hue documents connecting an agent’s own app clients to simulated services such as Calendar and Gmail. Verify the operations your case uses. Worlds in tests |
| Pricing | Free includes 500 monthly credits. Starter is $29/month, Team $99/month and Scale $299/month. Enterprise is scoped separately. Your target agent’s model provider bills separately. Pricing and credits | We could not verify a public rate for this workload in the product site or docs. Request terms for World instances, runs and hosted scoring at your intended volume. Hue · Documentation |
When to choose each
Choose Firedrill for a scheduling policy you can state ahead of time. You can specify two similar events, the user authorized to move one, and the exact fields that may change. A saved drill also gives you a repeatable case before you have customer traces.
Choose Hue to reproduce a specific episode involving an ambiguous event. Start from a checkpoint before the bad edit and inspect whether the history captured both events, their attendees and their original times. Hue also supports authored Worlds if history is incomplete.
Run a two-event calendar test
- Seed a synthetic calendar with two events titled “Budget review” on May 4, 2027. Event A starts at 10:00 UTC with Lee. Event B starts at 15:00 UTC with Jo. Ask “Move my budget review with Jo one hour later. Leave the other meeting alone.”
- Create that world in Firedrill. In Hue generate the same records or reconstruct an equivalent checkpoint from a synthetic trace. Read both event records before each run to verify identical inputs.
- Run three controls with the same reply, “I moved the meeting with Jo to 16:00 UTC.” One moves B to 16:00, one moves A instead, and one changes nothing. Require B at 16:00 and A untouched, including attendees. Expected verdicts are pass, fail, fail.
- Run your real agent on both platforms. Save the before-and-after event IDs, timestamps, reply, grade and evidence. Record a missing event snapshot as unassessable. Compare setup time for an authored case and the effort to reconstruct a case from history.