Hook Use Cases
Because hooks run as mechanism, they provide control that does not depend on the AI’s judgment. Four uses cover most cases.
1. Quality Gates
Run a check immediately after a change and refuse to continue when it does not meet the bar.
| Target | Check to run |
|---|---|
| After code changes | Tests, type checks, linters |
| After writing documents | Terminology checks, internal link validation |
| After config changes | Syntax checks, schema validation |
Unlike instructing the AI to “run the tests,” a hook cannot be skipped. Returning the check result to the AI also lets it correct the problem on the spot.
2. Safety Checks
Stop dangerous operations before they run.
- Abort writes to directories outside the allowed scope
- Present the target and request approval before a delete
- Halt when a connection to production is detected
Combined with tool permission design, this separates operations that are impossible by construction from operations blocked conditionally.
3. Recording
Capture what ran and when, automatically. Because no instruction is required, the record is always there when a problem needs tracing.
- Tools executed and their arguments
- The list of files changed
- Operations that requested approval, and the outcome
Records also feed evaluation, showing which steps fail most often from real data rather than impression.
4. Consistent Baseline
Load information that should always apply at session start.
- Project conventions and terminology rules
- The list of directories that must not be touched
- The current working branch or environment state
This removes the need to restate the baseline in every prompt, along with the variation that comes from forgetting to.
Keep Automatic Fixes Visible
When hooks apply formatting or corrections, what changed must remain visible. Silent rewrites mean unintended changes go unnoticed.
- Report the applied corrections in the output
- Limit corrections to changes that can be judged mechanically
Summary
- The main uses are quality gates, safety checks, recording, and a consistent baseline
- Unlike instructions, hooks cannot be skipped
- Records support both problem tracing and evaluation
- Keep automatic fixes visible so unintended changes surface