# Experiment > Start a new experiment with hypothesis and success criteria Use when this capability is needed. - Skill: `tomevault-io/experiment` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/experiment` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/experiment/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/experiment --- Before running the next experiment, document your plan: 1. State your **hypothesis** — what you expect to happen and why 2. Define **success criteria** — specific metrics and thresholds 3. Describe the **changes** you'll make from the current baseline After the experiment completes, append a line to `.distillate/runs.jsonl`: ```json {"$schema":"distillate/run/v1", "id":"run_NNN", "timestamp":"ISO8601", "status":"keep|discard|crash", "hypothesis":"...", "changes":"...", "hyperparameters":{...}, "results":{...}, "reasoning":"..."} ``` Set `status` to `keep` if results improved, `discard` if not, or `crash` on failure. Include `reasoning` to explain your decision. --- > Source: [rlacombe/distillate](https://github.com/rlacombe/distillate) — distributed by [TomeVault](https://tomevault.io).