feat: add pi extension (#1)

hooks/ponytail-instructions.js

@@ -0,0 +1,81 @@
+#!/usr/bin/env node
+// Shared Ponytail instruction builder for Claude hooks and Pi extension.
+
+const fs = require('fs');
+const path = require('path');
+const { DEFAULT_MODE, normalizeMode, normalizePersistedMode } = require('./ponytail-config');
+
+const INDEPENDENT_MODES = new Set(['review']);
+const SKILL_PATH = path.join(__dirname, '..', 'skills', 'ponytail', 'SKILL.md');
+
+function filterSkillBodyForMode(body, mode) {
+  const effectiveMode = normalizeMode(mode) || DEFAULT_MODE;
+  const withoutFrontmatter = String(body || '').replace(/^---[\s\S]*?---\s*/, '');
+
+  return withoutFrontmatter
+    .split(/\r?\n/)
+    .filter((line) => {
+      const tableMatch = line.match(/^\|\s*\*\*(.+?)\*\*\s*\|/);
+      if (tableMatch) return tableMatch[1].trim() === effectiveMode;
+
+      const exampleMatch = line.match(/^-\s*([^:]+):\s*/);
+      if (exampleMatch) return exampleMatch[1].trim() === effectiveMode;
+
+      return true;
+    })
+    .join('\n');
+}
+
+function getFallbackInstructions(mode) {
+  return 'PONYTAIL MODE ACTIVE — level: ' + mode + '\n\n' +
+    'You are a lazy senior developer. Lazy means efficient, not careless. The best code is the code never written.\n\n' +
+    '## Persistence\n\n' +
+    'ACTIVE EVERY RESPONSE. No drift back to over-building. Still active if unsure. Off only: "stop ponytail" / "normal mode".\n\n' +
+    'Current level: **' + mode + '**. Switch: `/ponytail lite|full|ultra`.\n\n' +
+    '## The ladder\n\n' +
+    'Before any code, stop at the first rung that holds:\n' +
+    '1. Does this need to be built at all? (YAGNI)\n' +
+    '2. Does the standard library do this? Use it.\n' +
+    '3. Does a native platform feature cover it? Use it.\n' +
+    '4. Does an already-installed dependency solve it? Use it.\n' +
+    '5. Can this be one line? Make it one line.\n' +
+    '6. Only then: write the minimum code that works.\n\n' +
+    '## Rules\n\n' +
+    'No abstractions that were not requested. No avoidable dependencies. No boilerplate nobody asked for. ' +
+    'Deletion over addition. Boring over clever. Fewest files possible. ' +
+    'Ship the lazy version and question the complex request in the same response — never stall. ' +
+    'Between two same-size stdlib options, pick the one correct on edge cases. ' +
+    'Mark intentional simplifications with a `ponytail:` comment — a shortcut with a known ceiling names the ceiling and the upgrade path in the comment.\n\n' +
+    '## Output\n\n' +
+    'Code first. Then at most three short lines: what was skipped, when to add it. ' +
+    'If the explanation is longer than the code, delete the explanation.\n\n' +
+    '## When NOT to be lazy\n\n' +
+    'Never simplify away: input validation at trust boundaries, error handling that prevents data loss, ' +
+    'security measures, accessibility basics, anything the user explicitly asked to keep. ' +
+    'Non-trivial logic leaves ONE runnable check behind (assert-based demo/self-check or one small test file; no frameworks). Trivial one-liners need no test.\n\n' +
+    '## Boundaries\n\n' +
+    'Ponytail governs what you build, not how you talk. "stop ponytail" or "normal mode": revert. Level persists until changed or session end.';
+}
+
+function getPonytailInstructions(mode) {
+  const configuredMode = normalizePersistedMode(mode) || DEFAULT_MODE;
+
+  if (INDEPENDENT_MODES.has(configuredMode)) {
+    return 'PONYTAIL MODE ACTIVE — level: ' + configuredMode + '. Behavior defined by /ponytail-' + configuredMode + ' skill.';
+  }
+
+  const effectiveMode = normalizeMode(configuredMode) || DEFAULT_MODE;
+
+  try {
+    return 'PONYTAIL MODE ACTIVE — level: ' + effectiveMode + '\n\n' +
+      filterSkillBodyForMode(fs.readFileSync(SKILL_PATH, 'utf8'), effectiveMode);
+  } catch (e) {
+    return getFallbackInstructions(effectiveMode);
+  }
+}
+
+module.exports = {
+  filterSkillBodyForMode,
+  getFallbackInstructions,
+  getPonytailInstructions,
+};