voyage/hooks/scripts/post-edit-check.mjs

#!/usr/bin/env node
// Hook: post-edit-check.mjs
// Event: PostToolUse (Edit, Write)
// Purpose: P7 -- after each edit, run the target repo's OWN formatter and
//   linter on the edited file (the fast tier of three: per file here / step
//   end and full in lib/verification/step-check.mjs, contract K9). Findings go
//   back to Claude next to the tool result (`decision: "block"`, hooks
//   reference section PostToolUse decision control); the edit itself already
//   happened, so the stop is at step end, where K9 exits 1 on them.
//   A file no configured, installed tool covers is "not measured" -- never
//   clean. Every result is logged in <git dir>/voyage/post-edit.jsonl for K9.
//
// On only while Voyage executes a plan in the repo, or when the repo has
// switched it on (hooks/lib/post-edit.mjs; operator decision 06.10). In every
// other session it exits at once and says nothing.
//
// Credit: running the formatter after Edit|Write is Anthropic's own documented
// hook pattern (hooks-guide); formatting per edit and the rest at step end is
// Cherny's; the cost tiers and "not measured" are agent-skills' (MIT); the
// per-file / step-end split is Kiro's. Ideas only.

import { readFileSync } from 'node:fs';
import { relative } from 'node:path';
import { resolveRepo, detectTools, toolsForFile, runTool, canonicalPath } from '../../lib/verification/repo-tools.mjs';
import { postEditActive, appendPostEditLog } from '../lib/post-edit.mjs';

let input;
try {
  input = JSON.parse(readFileSync(0, 'utf-8'));
} catch {
  process.exit(0);
}

const file = input?.tool_input?.file_path;
if (!file || typeof file !== 'string') process.exit(0);

const repo = resolveRepo(file);
if (!repo) process.exit(0);
const why = postEditActive(repo.root);
if (!why) process.exit(0);

const rel = relative(repo.root, canonicalPath(file));
const all = detectTools(repo.root);
const tools = toolsForFile(all, file);
const record = { ts: new Date().toISOString(), file: rel, on: why, session: input?.session_id ?? null };

function out(obj) {
  process.stdout.write(JSON.stringify(obj));
  process.exit(0);
}

if (tools.length === 0) {
  const missing = all.filter((t) => !t.available).map((t) => t.reason);
  appendPostEditLog(repo.gitDir, { ...record, status: 'not_measured', results: [], reason: missing.join('; ') || 'no tool for this file type' });
  out({
    hookSpecificOutput: {
      hookEventName: 'PostToolUse',
      additionalContext:
        `[voyage] post-edit check: not measured for ${rel} -- no formatter or linter for this file type is ` +
        `both configured and installed in this repository${missing.length ? ` (${missing.join('; ')})` : ''}.`,
    },
  });
}

const results = tools.map((t) => runTool(t, [rel], { cwd: repo.root, timeout: 30_000 }));
const findings = results.filter((r) => r.status === 'finding');
const errors = results.filter((r) => r.status === 'error');
const status = findings.length ? 'finding' : errors.length ? 'not_measured' : 'clean';
appendPostEditLog(repo.gitDir, { ...record, status, results: results.map(({ output, ...r }) => r) });

const errText = errors.length ? ` Not measured: ${errors.map((e) => `${e.name} could not run (exit ${e.exit})`).join('; ')}.` : '';

if (findings.length) {
  out({
    decision: 'block',
    reason:
      `[voyage] post-edit check found problems in ${rel}: ` +
      findings.map((f) => `${f.name} (${f.kind}): ${f.output.split('\n').slice(0, 15).join('\n')}`).join('\n') +
      `\nFix them before the step ends; the step check fails on them.${errText}`,
  });
}

out({
  hookSpecificOutput: {
    hookEventName: 'PostToolUse',
    additionalContext: status === 'clean'
      ? `[voyage] post-edit check clean for ${rel}: ${results.map((r) => r.name).join(', ')}.`
      : `[voyage] post-edit check for ${rel}:${errText}`,
  },
});