/ca-spike — exploratory spike

The sanctioned lane for "I need to write code to find out." Spike code is disposable by contract: it never merges, never PRs, and never becomes the implementation. What survives a spike is the answer, written down — the code is burned.

Flow

1. Name the question — a spike without a falsifiable question is just freelancing. Restate $ARGUMENTS as the question the spike answers and the timebox (default: one session). STOP for the user's confirmation.
2. Branch — create spike/<slug> from the current branch. All exploratory code and experiments stay on it; only the completed findings file may later cross back to the parent.
3. Explore — no tdd, no plan, no review fleet. Two rules survive even here: no secret leaves the approved store, and no irreversible operation (prod data, destructive migration) runs from a spike.
4. Exit — exactly one of:
   • Answered → write the findings to <project-root>/.codearbiter/spikes/<slug>.md (the question, what was tried, the answer, what it implies), and commit only that findings file on spike/<slug>. Return to the parent branch and run git restore --source spike/<slug> -- .codearbiter/spikes/<slug>.md to transfer only the committed findings file, review it, and commit that one file through /ca-commit; do not merge the spike branch. Then delete the spike branch. If the answer warrants building, hand the findings to /ca-feature — the spike file seeds brainstorming (<plugin-root>/routines/brainstorming/SKILL.md); the spike code is reference material, never the implementation.
   • Timebox expired, no answer → record that in the findings file and use the same findings-only transfer before deleting the spike branch.

Hard gate

MUST NOT merge or PR a spike/* branch — its only exits are a findings file and deletion. Do not transfer spike code: the parent may receive only the committed findings file. MUST NOT copy spike code into an implementation branch wholesale; implementation re-enters through /ca-feature and tdd. Secret-handling and irreversibility rules hold even in a spike. Commits on a spike/* branch are exempt from commit-gate — the exemption is safe because no spike commit is merged and the parent may copy only the committed findings file's contents, never spike code.

When NOT to use

• You already know what to build → /ca-feature.
• Diagnosing a defect → /ca-debug (investigation with a structured exit).
• A question answerable by reading code or docs → /ca-btw.