fix(fleet): boot-survival symmetry — disable-on-remove + add-enable + init-R5 (#612)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

docs/TASKS.md

@@ -58,3 +58,7 @@ Active workstream is **W1 — Federation v1**. Workers should:
 ## F3-m3 — mosaic update re-seeds framework + relaunches agents (#609) — feat/f3-m3-update-reseed
 
 - Status: implemented + tested. Closes R13: `mosaic update` now re-seeds the framework (data-safe MOSAIC_SYNC_ONLY) after the CLI install so shipped launcher/runtime changes activate; `--relaunch` restarts rostered agents; `--no-reseed` opts out. Detail: scratchpads/f3-m3-update-reseed.md.
+
+## Fleet-polish bundle — boot-survival symmetry (#611) — feat/fleet-polish-bundle
+
+- Status: implemented + tested. disable-on-remove (boot-resurrection bug, TDD) + add-enable + init-R5 hard guarantee. 4 new + 147 existing fleet tests green. Detail: scratchpads/fleet-polish-bundle.md.

docs/scratchpads/fleet-polish-bundle.md

@@ -0,0 +1,20 @@
+# Fleet-polish bundle — boot-survival symmetry (#611)
+
+- **Issue:** #611 · **Branch:** `feat/fleet-polish-bundle` · From the Lead's Codex symmetry-gap finding.
+
+## Three fixes
+
+1. **disable-on-remove (BUG, TDD).** `fleet remove` stopped + deleted roster/env/heartbeat but never
+   `systemctl --user disable mosaic-agent@NAME.service` → a removed-but-enabled unit could resurrect on
+   reboot pointing at deleted config. Fix: `buildSystemdDisableCommand` + disable in `remove`
+   (best-effort, gated on !--keep-files).
+2. **add-enable.** `fleet add` now enables the new agent's unit for boot-survival (best-effort,
+   independent of --start) — symmetry with disable-on-remove.
+3. **init-R5 guarantee.** `fleet init --write` now FAILS HARD when a non-minimal profile doesn't yield
+   exactly one orchestrator (was a soft warning). `minimal` (sanctioned no-orchestrator) still allowed.
+
+## Verification
+
+- 4 new tests (disable builder; remove-invokes-disable; add-invokes-enable; init general → exactly 1
+  orchestrator) + 147 existing fleet tests green (151 total). tsc/eslint/prettier clean.
+- TDD on the disable bug per contract.

packages/mosaic/src/commands/fleet.spec.ts

@@ -14,6 +14,7 @@ import {
   buildEnableLingerCommand,
   buildFleetServiceCommand,
   buildSystemdEnableCommand,
+  buildSystemdDisableCommand,
   buildSystemdShowCommand,
   buildTmuxListPanesCommand,
   buildTmuxListSessionsCommand,
@@ -983,6 +984,127 @@ describe('fleet ps — drift detection', () => {
   });
 });
 
+describe('fleet-polish bundle — boot-survival symmetry', () => {
+  async function rosterHome(agents: string): Promise<string> {
+    const home = await tempDir();
+    await mkdir(join(home, 'fleet'), { recursive: true });
+    await writeFile(join(home, 'fleet', 'roster.yaml'), agents);
+    return home;
+  }
+
+  it('buildSystemdDisableCommand returns the systemctl --user disable array', () => {
+    expect(buildSystemdDisableCommand('mosaic-agent@coder0.service')).toEqual([
+      'systemctl',
+      '--user',
+      'disable',
+      'mosaic-agent@coder0.service',
+    ]);
+  });
+
+  it('fleet remove DISABLES the unit so a removed agent cannot resurrect on boot', async () => {
+    const home = await rosterHome(
+      [
+        'version: 1',
+        'transport: tmux',
+        'agents:',
+        '  - name: orchestrator',
+        '    runtime: pi',
+        '    class: orchestrator',
+        '  - name: coder0',
+        '    runtime: codex',
+        '    class: worker',
+      ].join('\n') + '\n',
+    );
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+    try {
+      await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+      expect(calls).toContainEqual([
+        'systemctl',
+        '--user',
+        'disable',
+        'mosaic-agent@coder0.service',
+      ]);
+      // stop must still happen too
+      expect(calls).toContainEqual(['systemctl', '--user', 'stop', 'mosaic-agent@coder0.service']);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  it('fleet add ENABLES the new agent unit for boot-survival', async () => {
+    const home = await rosterHome(
+      ['version: 1', 'transport: tmux', 'agents:', '  - name: coder0', '    runtime: codex'].join(
+        '\n',
+      ) + '\n',
+    );
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+    try {
+      await program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'add',
+        'coder1',
+        '--runtime',
+        'codex',
+        '--class',
+        'worker',
+        '--no-start',
+      ]);
+      expect(calls).toContainEqual([
+        'systemctl',
+        '--user',
+        'enable',
+        'mosaic-agent@coder1.service',
+      ]);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  it('fleet init --write fails hard when a non-minimal profile lacks exactly one orchestrator', async () => {
+    // The general profile must yield exactly one orchestrator; the guarantee is
+    // enforced (not just warned). We assert the happy path writes cleanly.
+    const home = await tempDir();
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, {
+      runner: async () => ({ stdout: '', stderr: '', exitCode: 0 }),
+      mosaicHome: home,
+    });
+    try {
+      await program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'init',
+        '--profile',
+        'general',
+        '--write',
+      ]);
+      const written = await readFile(join(home, 'fleet', 'roster.yaml'), 'utf8');
+      const orchestrators = (written.match(/class:\s*orchestrator/g) ?? []).length;
+      expect(orchestrators).toBe(1);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+});
+
 describe('fleet install — auto-enable units for boot-survival', () => {
   it('buildSystemdEnableCommand and buildEnableLingerCommand return correct command arrays', () => {
     expect(buildSystemdEnableCommand('mosaic-tmux-holder.service')).toEqual([

packages/mosaic/src/commands/fleet.ts

@@ -227,6 +227,15 @@ export function buildSystemdEnableCommand(unit: string): string[] {
   return ['systemctl', '--user', 'enable', unit];
 }
 
+/**
+ * Returns the systemctl --user disable command for a given unit.
+ * Used by `fleet remove` so a removed agent's enabled unit cannot resurrect on
+ * boot pointing at deleted config (boot-survival symmetry with enable-on-add).
+ */
+export function buildSystemdDisableCommand(unit: string): string[] {
+  return ['systemctl', '--user', 'disable', unit];
+}
+
 /**
  * Returns the loginctl enable-linger command for a given user.
  * Linger allows user systemd services to survive logout.
@@ -872,15 +881,19 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
       await mkdir(dirname(destination), { recursive: true });
       await writeFile(destination, content);
 
-      // Validate: exactly one orchestrator required (R5) — friendly summary on success.
+      // Guarantee R5: exactly one orchestrator for every profile except the
+      // sanctioned no-orchestrator `minimal` preset. A mismatch means a
+      // corrupted/edited preset — fail hard rather than write a malformed fleet.
       const written = await loadFleetRoster(destination);
       const orchCount = countOrchestrators(written);
-      if (orchCount !== 1) {
-        process.stderr.write(
-          `Warning: fleet roster at ${destination} has ${orchCount} orchestrator agent(s) (expected exactly 1).\n`,
-        );
+      if (profile === 'minimal') {
         console.log(
-          `Initialized ${profile} fleet: ${written.agents.length} agent(s). Next: mosaic fleet install`,
+          `Initialized ${profile} fleet: ${written.agents.length} agent(s) (no orchestrator). Next: mosaic fleet install`,
+        );
+      } else if (orchCount !== 1) {
+        throw new Error(
+          `Fleet init failed: the "${profile}" roster has ${orchCount} orchestrator agent(s), ` +
+            `expected exactly 1 (R5). The preset may be corrupted — re-install the framework.`,
         );
       } else {
         const workerCount = written.agents.length - 1;
@@ -1218,6 +1231,24 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
 
         console.log(`Added ${name} (${opts.runtime}/${opts.class}) to the fleet.`);
 
+        // Enable the unit for boot-survival (non-fatal) — symmetry with
+        // disable-on-remove. Independent of --start so a queued agent still
+        // survives a reboot once its unit exists.
+        try {
+          const enableResult = await runner(
+            ...splitCommand(buildSystemdEnableCommand(`mosaic-agent@${name}.service`)),
+          );
+          if (enableResult.exitCode !== 0) {
+            process.stderr.write(
+              `Warning: could not enable mosaic-agent@${name}.service: ${enableResult.stderr || enableResult.stdout || 'non-zero exit'}\n`,
+            );
+          }
+        } catch (err) {
+          process.stderr.write(
+            `Warning: enable command failed for ${name}: ${err instanceof Error ? err.message : String(err)}\n`,
+          );
+        }
+
         if (opts.start !== false) {
           await runChecked(runner, buildFleetServiceCommand('start', name));
           console.log(`Started mosaic-agent@${name}.service.`);
@@ -1254,6 +1285,26 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
         );
       }
 
+      // Disable the unit (non-fatal) so an enabled instance cannot resurrect on
+      // boot pointing at the now-deleted config — boot-survival symmetry with
+      // enable-on-add. Skipped only when --keep-files keeps the config in place.
+      if (!opts.keepFiles) {
+        try {
+          const disableResult = await runner(
+            ...splitCommand(buildSystemdDisableCommand(`mosaic-agent@${name}.service`)),
+          );
+          if (disableResult.exitCode !== 0) {
+            process.stderr.write(
+              `Warning: could not disable mosaic-agent@${name}.service: ${disableResult.stderr || disableResult.stdout || 'non-zero exit'}\n`,
+            );
+          }
+        } catch (err) {
+          process.stderr.write(
+            `Warning: disable command failed for ${name}: ${err instanceof Error ? err.message : String(err)}\n`,
+          );
+        }
+      }
+
       // Write updated roster
       await writeFile(rosterPath, serializeRosterToYaml(updatedRoster));