fix(fleet): enforce exact comms authority (#787)

packages/mosaic/src/commands/launch.ts

@@ -19,10 +19,17 @@ import { createRequire } from 'node:module';
 import { homedir } from 'node:os';
 import { join, dirname } from 'node:path';
 import type { Command } from 'commander';
-import { readFleetCommsBlock } from '../fleet/comms-onboarding.js';
+import {
+  buildResolvedFleetCommsBlock,
+  renderToolsContractStatus,
+  resolveFleetIdentity,
+} from '../fleet/comms-onboarding.js';
+import { readRegularFileSecure } from '../fleet/secure-file.js';
 import { readPersonaContractBlock } from '../fleet/persona-contract.js';
+import { canonicalizeRoleClass } from './fleet-personas.js';
 
 const MOSAIC_HOME = process.env['MOSAIC_HOME'] ?? join(homedir(), '.config', 'mosaic');
+const MAX_INSTALLED_TOOLS_BYTES = 256 * 1024;
 
 type RuntimeName = 'claude' | 'codex' | 'opencode' | 'pi';
 
@@ -185,6 +192,17 @@ function readOptional(path: string): string {
   }
 }
 
+function readInstalledToolsSecure(mosaicHome: string): string {
+  try {
+    return readRegularFileSecure(join(mosaicHome, 'TOOLS.md'), {
+      root: mosaicHome,
+      maxBytes: MAX_INSTALLED_TOOLS_BYTES,
+    }).content.toString('utf8');
+  } catch {
+    return '';
+  }
+}
+
 function readJson(path: string): Record<string, unknown> | null {
   try {
     return JSON.parse(readFileSync(path, 'utf-8')) as Record<string, unknown>;
@@ -361,9 +379,25 @@ For required push/merge/issue-close/release actions, execute without routine con
     parts.push('\n\n## Operator Overlay (USER.local.md)\n\n' + userLocal);
   }
 
+  const fleetIdentity = resolveFleetIdentity(mosaicHome, process.env['MOSAIC_AGENT_NAME']);
+  if (!fleetIdentity.ok) {
+    throw new Error(`Fleet communications contract unavailable: ${fleetIdentity.error}`);
+  }
+  const canonicalMember = fleetIdentity.identity?.member;
+  if (canonicalMember && process.env['MOSAIC_AGENT_CLASS']?.trim()) {
+    const ambientClass = canonicalizeRoleClass(process.env['MOSAIC_AGENT_CLASS']).canonicalClass;
+    if (ambientClass !== canonicalMember.className) {
+      throw new Error(
+        `Ambient MOSAIC_AGENT_CLASS resolves to "${ambientClass}" but canonical roster member "${canonicalMember.name}" resolves to "${canonicalMember.className}". Refusing split identity authority.`,
+      );
+    }
+  }
+
   // TOOLS.md
-  const tools = readOptional(join(mosaicHome, 'TOOLS.md'));
+  const tools = readInstalledToolsSecure(mosaicHome);
   if (tools) parts.push('\n\n# Machine Tools\n\n' + tools);
+  const toolsContractStatus = renderToolsContractStatus(mosaicHome);
+  if (toolsContractStatus) parts.push('\n\n' + toolsContractStatus);
 
   // Operator overlays whose base layers are load-on-demand (SOUL, STANDARDS):
   // inject only the small `.local` delta by value so the customization reaches
@@ -385,24 +419,23 @@ For required push/merge/issue-close/release actions, execute without routine con
   // Runtime-specific contract
   parts.push('\n\n# Runtime-Specific Contract\n\n' + readFileSync(runtimeFile, 'utf-8'));
 
-  // Persona contract (A3b): when this agent was spawned with a class
-  // (MOSAIC_AGENT_CLASS, exported into the pane env by A3a), inject its resolved
-  // role contract so its identity (mandate + boundaries) is resident from the
-  // first turn. Override-aware via the persona resolver: a user-customized
-  // persona in fleet/roles.local/ wins over the baseline (AC-NS-7 launch proof).
-  // Placed BEFORE fleet comms: identity first, then how-to-reach-peers. No-ops
-  // silently when the class is unset/unknown (mirrors the comms block).
-  const persona = readPersonaContractBlock(mosaicHome, process.env['MOSAIC_AGENT_CLASS']);
+  // Fleet launches derive every identity projection from the one canonical roster
+  // member resolved above. Non-fleet launches retain the legacy ambient persona
+  // and tool-policy behavior.
+  const personaClass = canonicalMember?.className ?? process.env['MOSAIC_AGENT_CLASS'];
+  const persona = readPersonaContractBlock(mosaicHome, personaClass);
   if (persona) parts.push('\n\n' + persona);
 
-  const toolPolicy = readFleetToolPolicyBlock(process.env['MOSAIC_AGENT_TOOL_POLICY']);
+  const toolPolicyName = canonicalMember
+    ? canonicalMember.toolPolicy
+    : process.env['MOSAIC_AGENT_TOOL_POLICY'];
+  const toolPolicy = readFleetToolPolicyBlock(toolPolicyName);
   if (toolPolicy) parts.push('\n\n' + toolPolicy);
 
-  // Fleet onboarding: when this is a spawned fleet agent (MOSAIC_AGENT_NAME set
-  // and present in the roster), inject a comms cheat-sheet + peer roster so it
-  // knows how to reach the orchestrator and its peers from its first turn.
-  const fleetComms = readFleetCommsBlock(mosaicHome, process.env['MOSAIC_AGENT_NAME']);
-  if (fleetComms) parts.push('\n\n' + fleetComms);
+  if (fleetIdentity.identity) {
+    const fleetComms = buildResolvedFleetCommsBlock(fleetIdentity.identity);
+    if (fleetComms) parts.push('\n\n' + fleetComms);
+  }
 
   return parts.join('\n');
 }