feat(fleet): add shared role semantics (#768)

packages/mosaic/src/fleet/roster-v2.ts

@@ -1,4 +1,15 @@
 import YAML from 'yaml';
+import {
+  authorityForCanonicalClass,
+  canonicalizeRoleClass,
+  defaultOverrideDir,
+  defaultRolesDir,
+  extractClassesFromDir,
+  resolvePersonaFrom,
+  type PersonaDirs,
+  type PersonaResolution,
+  type RoleAuthority,
+} from '../commands/fleet-personas.js';
 
 export const ROSTER_V2_SUPPORTED_RUNTIMES = ['claude', 'codex', 'opencode', 'pi'] as const;
 export const ROSTER_V2_REASONING_LEVELS = ['low', 'medium', 'high'] as const;
@@ -58,6 +69,80 @@ export interface FleetRosterV2 {
   readonly agents: readonly FleetRosterV2Agent[];
 }
 
+export interface SemanticallyValidatedRosterV2Agent extends FleetRosterV2Agent {
+  readonly requestedClass: string;
+  readonly canonicalClass: string;
+  readonly canonicalToolPolicy: string;
+  readonly persona: PersonaResolution;
+  readonly authority: RoleAuthority;
+}
+
+export interface SemanticallyValidatedRosterV2 extends Omit<FleetRosterV2, 'agents'> {
+  readonly agents: readonly SemanticallyValidatedRosterV2Agent[];
+}
+
+const PROTECTED_TOOL_POLICY_CLASSES = new Set([
+  'merge-gate',
+  'validator',
+  'orchestrator',
+  'team-leader',
+  'interaction',
+]);
+
+/**
+ * Validate filesystem-backed roster semantics after synchronous structural parsing.
+ * Directory scans are batched once and every class must resolve to readable content.
+ */
+export async function validateRosterV2Semantics(
+  roster: FleetRosterV2,
+  opts: PersonaDirs = {},
+): Promise<SemanticallyValidatedRosterV2> {
+  const rolesDir = opts.rolesDir ?? defaultRolesDir(opts.mosaicHome);
+  const overrideDir = opts.overrideDir ?? defaultOverrideDir(opts.mosaicHome);
+  const [base, over] = await Promise.all([
+    extractClassesFromDir(rolesDir),
+    extractClassesFromDir(overrideDir),
+  ]);
+
+  const agents: SemanticallyValidatedRosterV2Agent[] = [];
+  for (const agent of roster.agents) {
+    const requestedClass = agent.className;
+    const { canonicalClass } = canonicalizeRoleClass(requestedClass);
+    const canonicalToolPolicy = canonicalizeRoleClass(agent.toolPolicy).canonicalClass;
+    const persona = await resolvePersonaFrom(requestedClass, {
+      rolesDir,
+      overrideDir,
+      base,
+      over,
+    });
+    if (!persona || persona.content.trim() === '') {
+      throw new RosterV2ValidationError(
+        `Roster v2 agent "${agent.name}" class "${requestedClass}" does not resolve to a readable persona.`,
+      );
+    }
+    if (
+      (PROTECTED_TOOL_POLICY_CLASSES.has(canonicalClass) ||
+        PROTECTED_TOOL_POLICY_CLASSES.has(canonicalToolPolicy)) &&
+      canonicalToolPolicy !== canonicalClass
+    ) {
+      throw new RosterV2ValidationError(
+        `Roster v2 agent "${agent.name}" protected class "${canonicalClass}" tool policy must match its canonical class; received "${agent.toolPolicy}".`,
+      );
+    }
+    agents.push(
+      Object.freeze({
+        ...agent,
+        requestedClass,
+        canonicalClass,
+        canonicalToolPolicy,
+        persona,
+        authority: authorityForCanonicalClass(canonicalClass),
+      }),
+    );
+  }
+  return Object.freeze({ ...roster, agents: Object.freeze(agents) });
+}
+
 export class RosterV2ValidationError extends Error {
   constructor(message: string) {
     super(message);