fix: regenerate pi-claude-cli MCP config per session and auto-sync skill tools

The MCP config was generated lazily once and locked, so engine session-scoped
tools (fn_review_spec, fn_review_step) never reached the Claude CLI subprocess
and triage/executor sessions failed with "unknown tool" errors. Now the config
is hashed per call and rewritten when the tool set changes.

Also adds scripts/sync-fusion-skill-tools.mjs to regenerate the SKILL.md
tool-categories block from extension.ts at build time, with a --check mode
wired into skill-sync tests so drift fails CI.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/sync-fusion-skill-tools.mjs

@@ -0,0 +1,141 @@
+#!/usr/bin/env node
+/**
+ * Regenerates the `tool-categories` block in the Fusion skill SKILL.md from
+ * the canonical list of `fn_*` tools registered in `packages/cli/src/extension.ts`.
+ *
+ * Source of truth: extension.ts (each tool is registered with `name: "fn_..."`).
+ * Output: the `<!-- BEGIN: tool-categories ... -->` / `<!-- END: tool-categories -->`
+ * block inside `packages/cli/skill/fusion/SKILL.md`.
+ *
+ * The `.claude/skills/fusion` path is a symlink to `packages/cli/skill/fusion`,
+ * so it picks up the change automatically.
+ *
+ * Usage:
+ *   node scripts/sync-fusion-skill-tools.mjs           # rewrite SKILL.md in place
+ *   node scripts/sync-fusion-skill-tools.mjs --check   # exit 1 if drift detected
+ *
+ * Wired into `packages/cli` build via the `prebuild` script so a fresh build
+ * always emits an up-to-date skill, and CI catches drift via `--check`.
+ */
+
+import { readFileSync, writeFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, resolve } from "node:path";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const repoRoot = resolve(__dirname, "..");
+const extensionPath = resolve(repoRoot, "packages/cli/src/extension.ts");
+const skillPath = resolve(repoRoot, "packages/cli/skill/fusion/SKILL.md");
+
+const BEGIN_MARKER =
+  "<!-- BEGIN: tool-categories (auto-generated by scripts/sync-fusion-skill-tools.mjs — do not edit by hand) -->";
+const END_MARKER = "<!-- END: tool-categories -->";
+
+/**
+ * Categorize a tool name into one of the published skill categories.
+ * The order of categories here defines the order of bullets in SKILL.md.
+ */
+function categorize(name) {
+  if (name.includes("github")) return "GitHub";
+  if (name.startsWith("fn_task_")) return "Task";
+  if (
+    name.startsWith("fn_mission_") ||
+    name.startsWith("fn_milestone_") ||
+    name.startsWith("fn_slice_") ||
+    name.startsWith("fn_feature_")
+  ) {
+    return "Mission";
+  }
+  if (name.startsWith("fn_agent_")) return "Agent";
+  if (name.startsWith("fn_skills_")) return "Skills";
+  return "Other";
+}
+
+const CATEGORY_ORDER = ["Task", "GitHub", "Mission", "Agent", "Skills", "Other"];
+const CATEGORY_LABELS = {
+  Task: "Task tools",
+  GitHub: "GitHub tools",
+  Mission: "Mission tools",
+  Agent: "Agent tools",
+  Skills: "Skills tools",
+  Other: "Other tools",
+};
+
+function extractToolNames(source) {
+  const names = [];
+  for (const match of source.matchAll(/name:\s*"(fn_[a-z_]+)"/g)) {
+    names.push(match[1]);
+  }
+  if (names.length === 0) {
+    throw new Error(
+      `No fn_* tool registrations found in ${extensionPath} — refusing to wipe the skill.`,
+    );
+  }
+  return names;
+}
+
+function buildBlock(toolNames) {
+  const grouped = new Map(CATEGORY_ORDER.map((c) => [c, []]));
+  for (const name of toolNames) {
+    grouped.get(categorize(name)).push(name);
+  }
+  const lines = [BEGIN_MARKER];
+  for (const category of CATEGORY_ORDER) {
+    const tools = grouped.get(category);
+    if (tools.length === 0) continue;
+    const formatted = tools.map((t) => `\`${t}\``).join(", ");
+    lines.push(`- **${CATEGORY_LABELS[category]}** — ${formatted}`);
+  }
+  lines.push(END_MARKER);
+  return lines.join("\n");
+}
+
+function replaceBlock(skillContent, newBlock) {
+  const beginIdx = skillContent.indexOf(BEGIN_MARKER);
+  const endIdx = skillContent.indexOf(END_MARKER);
+  if (beginIdx === -1 || endIdx === -1 || endIdx < beginIdx) {
+    throw new Error(
+      `Could not find BEGIN/END tool-categories markers in ${skillPath}. ` +
+        `Add them around the tool-categories bullet list.`,
+    );
+  }
+  const endLineEnd = endIdx + END_MARKER.length;
+  return (
+    skillContent.slice(0, beginIdx) + newBlock + skillContent.slice(endLineEnd)
+  );
+}
+
+function main() {
+  const checkOnly = process.argv.includes("--check");
+
+  const source = readFileSync(extensionPath, "utf-8");
+  const skillContent = readFileSync(skillPath, "utf-8");
+
+  const toolNames = extractToolNames(source);
+  const newBlock = buildBlock(toolNames);
+  const updated = replaceBlock(skillContent, newBlock);
+
+  if (updated === skillContent) {
+    if (!checkOnly) {
+      console.log(
+        `[sync-fusion-skill-tools] SKILL.md tool-categories block is already up to date (${toolNames.length} tools).`,
+      );
+    }
+    return;
+  }
+
+  if (checkOnly) {
+    console.error(
+      `[sync-fusion-skill-tools] SKILL.md tool-categories block is out of date.\n` +
+        `Run \`node scripts/sync-fusion-skill-tools.mjs\` to regenerate it.`,
+    );
+    process.exit(1);
+  }
+
+  writeFileSync(skillPath, updated);
+  console.log(
+    `[sync-fusion-skill-tools] Rewrote tool-categories block in ${skillPath} (${toolNames.length} tools).`,
+  );
+}
+
+main();