feat(optimization): implement manifest-driven extraction pipeline

- Implement `extract.ts` with robust character-aware parsing for snippets and tools.
- Consolidate research dependencies by moving `@ax-llm/ax` to root `optionalDependencies`.
- Relocate evaluation logic from `packages/core` to `scripts/optimization/lib/evals` to keep the production core lean.
- Add `optimization_targets` to `data/manifest.json` as the single source of truth for the pipeline.
- Implement comprehensive unit tests for extraction and variable masking with 100% pass rate.
- Update global config and linting rules to support the new optimization infrastructure.

scripts/optimization/extract.ts

@@ -0,0 +1,175 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { maskVariables } from './lib/masking.js';
+
+export interface OptimizationTarget {
+  id: string;
+  sourceFile: string;
+  originalText: string;
+  maskedText: string;
+  maskMap: Record<string, string>;
+}
+
+/**
+ * Robustly finds a block bounded by { } using character scanning.
+ */
+function findBlockBounds(
+  content: string,
+  startIdx: number,
+): { start: number; end: number } | null {
+  const blockStart = content.indexOf('{', startIdx);
+  if (blockStart === -1) return null;
+
+  let braceCount = 0;
+  for (let i = blockStart; i < content.length; i++) {
+    if (content[i] === '{') braceCount++;
+    if (content[i] === '}') braceCount--;
+    if (braceCount === 0) {
+      return { start: blockStart, end: i };
+    }
+  }
+  return null;
+}
+
+/**
+ * Main extraction function.
+ */
+export async function runExtraction() {
+  const manifest = JSON.parse(fs.readFileSync('data/manifest.json', 'utf8'));
+  const targets: OptimizationTarget[] = [];
+
+  // 1. Snippets
+  const snippetNames =
+    manifest.data_inventory?.optimization_targets?.snippets || [];
+  const snippetsPath = 'packages/core/src/prompts/snippets.ts';
+  if (fs.existsSync(snippetsPath)) {
+    const content = fs.readFileSync(snippetsPath, 'utf8');
+    for (const name of snippetNames) {
+      const startIdx = content.indexOf(`export function ${name}`);
+      if (startIdx === -1) continue;
+
+      const bounds = findBlockBounds(content, startIdx);
+      if (!bounds) continue;
+
+      const body = content.substring(bounds.start, bounds.end + 1);
+      // Capture the LAST template literal
+      const tickMatches = [...body.matchAll(/`((?:[^`\\]|\\.)*)`/g)];
+      if (tickMatches.length > 0) {
+        const text = tickMatches[tickMatches.length - 1][1].trim();
+        const { maskedText, maskMap } = maskVariables(text);
+        targets.push({
+          id: `snippets:${name}`,
+          sourceFile: snippetsPath,
+          originalText: text,
+          maskedText,
+          maskMap,
+        });
+      }
+    }
+  }
+
+  // 2. Tools
+  const toolNames = Object.keys(manifest.data_inventory?.tools || {});
+  const gemini3Path =
+    'packages/core/src/tools/definitions/model-family-sets/gemini-3.ts';
+  if (fs.existsSync(gemini3Path)) {
+    const content = fs.readFileSync(gemini3Path, 'utf8');
+    for (const name of toolNames) {
+      // Find tool key (2-space indent)
+      const toolRegex = new RegExp(`^\\s{2}${name}:\\s*\\{`, 'm');
+      const match = toolRegex.exec(content);
+      if (!match) continue;
+
+      const bounds = findBlockBounds(content, match.index);
+      if (!bounds) continue;
+
+      const toolBlock = content.substring(match.index, bounds.end + 1);
+      const descRegex =
+        /description:\s*(?:`((?:[^`\\]|\\.)*)`|'([^']*)'|"([^"]*)")/g;
+      const descMatch = descRegex.exec(toolBlock);
+
+      if (descMatch) {
+        const text = (descMatch[1] || descMatch[2] || descMatch[3]).trim();
+        const { maskedText, maskMap } = maskVariables(text);
+        targets.push({
+          id: `gemini3:${name}:description`,
+          sourceFile: gemini3Path,
+          originalText: text,
+          maskedText,
+          maskMap,
+        });
+      }
+    }
+  }
+
+  // 3. Dynamic Helpers
+  const helpersPath =
+    'packages/core/src/tools/definitions/dynamic-declaration-helpers.ts';
+  if (fs.existsSync(helpersPath)) {
+    const content = fs.readFileSync(helpersPath, 'utf8');
+    const specs = [
+      {
+        id: 'shell:darwin:description',
+        regex:
+          /return `This tool executes a given shell command as \\`bash -c <command>\\`. ([\s\S]*?)`;/,
+      },
+      {
+        id: 'shell:win32:description',
+        regex:
+          /return `This tool executes a given shell command as \\`powershell\.exe -NoProfile -Command <command>\\`. ([\s\S]*?)`;/,
+      },
+      {
+        id: 'exit_plan_mode:description',
+        regex:
+          /name: EXIT_PLAN_MODE_TOOL_NAME,[\s\S]*?description:\s*'([^']*)',/,
+      },
+      {
+        id: 'activate_skill:description',
+        regex:
+          /name: ACTIVATE_SKILL_TOOL_NAME,[\s\S]*?description:\s*`((?:[^`\\]|\\.)*)`,/,
+      },
+    ];
+    for (const s of specs) {
+      const m = s.regex.exec(content);
+      if (m && m[1]) {
+        const text = m[1].trim();
+        const { maskedText, maskMap } = maskVariables(text);
+        targets.push({
+          id: s.id,
+          sourceFile: helpersPath,
+          originalText: text,
+          maskedText,
+          maskMap,
+        });
+      }
+    }
+  }
+
+  const outputDir = 'data/optimization';
+  if (!fs.existsSync(outputDir)) fs.mkdirSync(outputDir, { recursive: true });
+
+  fs.writeFileSync(
+    path.join(outputDir, 'targets.json'),
+    JSON.stringify(targets, null, 2),
+  );
+  return targets;
+}
+
+// CLI Entrypoint
+const isMain =
+  process.argv[1] &&
+  fileURLToPath(import.meta.url) === fs.realpathSync(process.argv[1]);
+if (isMain) {
+  runExtraction()
+    // eslint-disable-next-line no-console
+    .then((t) => console.log(`✅ Extracted ${t.length} targets.`))
+    // eslint-disable-next-line no-console
+    .catch(console.error);
+}