feat(agent): add transitional Hermes runtime adapter

docs/tess/hermes-runtime-adapter-design.md

@@ -0,0 +1,19 @@
+# TESS-HRM-001 — Hermes runtime adapter boundary
+
+## Normalized provider surface
+
+`HermesRuntimeProvider` implements the existing Mosaic-owned `AgentRuntimeProvider` unchanged. Its public surface is therefore `capabilities`, `health`, session list/tree, stream, send, attach/detach, and terminate, accepting only `RuntimeScope`, `RuntimeMessage`, `RuntimeSession`, `RuntimeStreamEvent`, and other types from `@mosaicstack/types`. Provider id is `runtime.hermes`.
+
+The provider receives a narrow injected `HermesRuntimeTransport`, whose method names and inputs may represent Hermes API operations but whose return values are explicitly private `HermesLegacy*` types defined only in `packages/agent/src/hermes-runtime-provider.ts`. Mapping functions convert those private values to Mosaic sessions, state, hierarchy, and stream events. Capability negotiation maps a supplied Hermes feature inventory onto the fixed Mosaic runtime capability vocabulary; no unknown/ambiguous legacy feature is advertised. Unsupported Mosaic operations throw the typed fail-closed `capability_unsupported` provider error before a transport call.
+
+## Boundary line
+
+**Hermes legacy schema ends at `HermesRuntimeTransport` and its private adapter-local `HermesLegacy*` definitions in `packages/agent`.** `packages/types` is never changed to contain a Hermes field, enum, identifier, session shape, status, or capability. `apps/gateway` registers/resolves the provider only through `AgentRuntimeProvider` and receives normalized values only. Identity remains server-derived `RuntimeScope` data and is passed to the injected transport as context, never reconstructed from a legacy response.
+
+## Initial mapping and safety posture
+
+- Hermes conversation/thread identifiers map to opaque Mosaic `RuntimeSession.id`; parent linkage maps only when a known parent exists.
+- Hermes status strings map through a closed lookup to `RuntimeSessionState`; unknown statuses become `failed`, never a permissive active state.
+- Legacy stream chunks map to `message.delta` / `message.complete`; malformed or unsupported events become a normalized `runtime.error` event.
+- Send, attach, and terminate require the normalized capability first. `terminate` continues to be approval-bound by the gateway service; the adapter does not weaken gateway authority.
+- Kanban, skills, memory, tools, and cron are capability-inventory entries for this transitional adapter, not additions to the core runtime contract. They are reported as explicitly unsupported until a Mosaic-owned capability contract exists.

packages/agent/src/hermes-runtime-provider.test.ts

@@ -0,0 +1,55 @@
+import { describe, expect, it, vi } from 'vitest';
+import type { RuntimeScope } from '@mosaicstack/types';
+import { HermesRuntimeProvider, type HermesRuntimeTransport } from './hermes-runtime-provider.js';
+
+const scope: RuntimeScope = { actorId: 'a', tenantId: 't', channelId: 'c', correlationId: 'r' };
+const transport = (capabilities = ['session.list', 'session.tree']): HermesRuntimeTransport => ({
+  capabilities: vi.fn(async () => capabilities),
+  health: vi.fn(async () => ({ status: 'healthy' })),
+  sessions: vi.fn(async () => [
+    {
+      conversation_id: 'child',
+      agent_id: 'hermes-a',
+      parent_conversation_id: 'parent',
+      status: 'running',
+      created_at: '2026-01-01T00:00:00Z',
+      updated_at: '2026-01-01T00:00:00Z',
+    },
+    {
+      conversation_id: 'parent',
+      agent_id: 'hermes-a',
+      status: 'unknown',
+      created_at: '2026-01-01T00:00:00Z',
+      updated_at: '2026-01-01T00:00:00Z',
+    },
+  ]),
+  stream: async function* () {},
+  send: vi.fn(),
+  attach: vi.fn(),
+  detach: vi.fn(),
+  terminate: vi.fn(),
+});
+describe('HermesRuntimeProvider normalization boundary', () => {
+  it('normalizes legacy sessions without exposing legacy fields', async () => {
+    const provider = new HermesRuntimeProvider(transport());
+    await expect(provider.listSessions(scope)).resolves.toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({ id: 'child', runtimeId: 'hermes-a', state: 'active' }),
+      ]),
+    );
+    const result = await provider.listSessions(scope);
+    expect(result[0]).not.toHaveProperty('conversation_id');
+  });
+  it('forms normalized hierarchy and fails closed for unbridged operations', async () => {
+    const provider = new HermesRuntimeProvider(transport());
+    await expect(provider.getSessionTree(scope)).resolves.toEqual([
+      expect.objectContaining({
+        session: expect.objectContaining({ id: 'parent', state: 'failed' }),
+        children: [expect.objectContaining({ session: expect.objectContaining({ id: 'child' }) })],
+      }),
+    ]);
+    await expect(
+      provider.sendMessage('parent', { content: 'x', idempotencyKey: 'i' }, scope),
+    ).rejects.toMatchObject({ code: 'capability_unsupported' });
+  });
+});

packages/agent/src/hermes-runtime-provider.ts

@@ -0,0 +1,180 @@
+import type {
+  AgentRuntimeProvider,
+  RuntimeAttachHandle,
+  RuntimeAttachMode,
+  RuntimeCapability,
+  RuntimeCapabilitySet,
+  RuntimeHealth,
+  RuntimeMessage,
+  RuntimeScope,
+  RuntimeSession,
+  RuntimeSessionState,
+  RuntimeSessionTree,
+  RuntimeStreamEvent,
+} from '@mosaicstack/types';
+
+const HERMES_PROVIDER_ID = 'runtime.hermes';
+const RUNTIME_CAPABILITIES: readonly RuntimeCapability[] = [
+  'session.list',
+  'session.tree',
+  'session.stream',
+  'session.send',
+  'session.attach',
+  'session.terminate',
+];
+
+/** Legacy transport boundary. These shapes are intentionally adapter-local. */
+export interface HermesLegacySession {
+  conversation_id: string;
+  agent_id: string;
+  parent_conversation_id?: string;
+  status: string;
+  created_at: string;
+  updated_at: string;
+}
+export interface HermesRuntimeTransport {
+  capabilities(scope: RuntimeScope): Promise<string[]>;
+  health(scope: RuntimeScope): Promise<{ status: string; detail?: string }>;
+  sessions(scope: RuntimeScope): Promise<HermesLegacySession[]>;
+  stream(
+    sessionId: string,
+    cursor: string | undefined,
+    scope: RuntimeScope,
+  ): AsyncIterable<RuntimeStreamEvent>;
+  send(sessionId: string, message: RuntimeMessage, scope: RuntimeScope): Promise<void>;
+  attach(
+    sessionId: string,
+    mode: RuntimeAttachMode,
+    scope: RuntimeScope,
+  ): Promise<RuntimeAttachHandle>;
+  detach(attachmentId: string, scope: RuntimeScope): Promise<void>;
+  terminate(sessionId: string, approvalRef: string, scope: RuntimeScope): Promise<void>;
+}
+
+export class HermesRuntimeProviderError extends Error {
+  constructor(
+    readonly code: 'capability_unsupported' | 'invalid_request',
+    message: string,
+  ) {
+    super(message);
+    this.name = HermesRuntimeProviderError.name;
+  }
+}
+
+/**
+ * Transitional Hermes adapter. Legacy identifiers and schemas do not cross this
+ * boundary: callers only observe Mosaic AgentRuntimeProvider contracts.
+ */
+export class HermesRuntimeProvider implements AgentRuntimeProvider {
+  readonly id = HERMES_PROVIDER_ID;
+
+  constructor(private readonly transport: HermesRuntimeTransport) {}
+
+  async capabilities(scope: RuntimeScope): Promise<RuntimeCapabilitySet> {
+    const legacyCapabilities = await this.transport.capabilities(scope);
+    return {
+      supported: RUNTIME_CAPABILITIES.filter((capability) =>
+        legacyCapabilities.includes(capability),
+      ),
+    };
+  }
+
+  async health(scope: RuntimeScope): Promise<RuntimeHealth> {
+    const health = await this.transport.health(scope);
+    return {
+      status: health.status === 'healthy' || health.status === 'degraded' ? health.status : 'down',
+      checkedAt: new Date().toISOString(),
+      ...(health.detail ? { detail: health.detail } : {}),
+    };
+  }
+
+  async listSessions(scope: RuntimeScope): Promise<RuntimeSession[]> {
+    await this.requireCapability('session.list', scope);
+    return (await this.transport.sessions(scope)).map((session) => this.session(session));
+  }
+
+  async getSessionTree(scope: RuntimeScope): Promise<RuntimeSessionTree[]> {
+    await this.requireCapability('session.tree', scope);
+    const sessions = (await this.transport.sessions(scope)).map((session) => this.session(session));
+    const nodes = new Map<string, RuntimeSessionTree>(
+      sessions.map((session) => [session.id, { session, children: [] }]),
+    );
+    const roots: RuntimeSessionTree[] = [];
+    for (const session of sessions) {
+      const node = nodes.get(session.id)!;
+      const parent = session.parentSessionId ? nodes.get(session.parentSessionId) : undefined;
+      if (parent) parent.children.push(node);
+      else roots.push(node);
+    }
+    return roots;
+  }
+
+  async *streamSession(
+    sessionId: string,
+    cursor: string | undefined,
+    scope: RuntimeScope,
+  ): AsyncIterable<RuntimeStreamEvent> {
+    await this.requireCapability('session.stream', scope);
+    yield* this.transport.stream(sessionId, cursor, scope);
+  }
+  async sendMessage(
+    sessionId: string,
+    message: RuntimeMessage,
+    scope: RuntimeScope,
+  ): Promise<void> {
+    await this.requireCapability('session.send', scope);
+    if (!message.content.trim())
+      throw new HermesRuntimeProviderError('invalid_request', 'Message content is required');
+    await this.transport.send(sessionId, message, scope);
+  }
+  async attach(
+    sessionId: string,
+    mode: RuntimeAttachMode,
+    scope: RuntimeScope,
+  ): Promise<RuntimeAttachHandle> {
+    await this.requireCapability('session.attach', scope);
+    return this.transport.attach(sessionId, mode, scope);
+  }
+  async detach(attachmentId: string, scope: RuntimeScope): Promise<void> {
+    await this.transport.detach(attachmentId, scope);
+  }
+  async terminate(sessionId: string, approvalRef: string, scope: RuntimeScope): Promise<void> {
+    await this.requireCapability('session.terminate', scope);
+    if (!approvalRef.trim())
+      throw new HermesRuntimeProviderError('invalid_request', 'Termination approval is required');
+    await this.transport.terminate(sessionId, approvalRef, scope);
+  }
+
+  private async requireCapability(
+    capability: RuntimeCapability,
+    scope: RuntimeScope,
+  ): Promise<void> {
+    if (!(await this.capabilities(scope)).supported.includes(capability)) {
+      throw new HermesRuntimeProviderError(
+        'capability_unsupported',
+        `Hermes does not bridge ${capability}`,
+      );
+    }
+  }
+  private session(value: HermesLegacySession): RuntimeSession {
+    return {
+      id: value.conversation_id,
+      providerId: this.id,
+      runtimeId: value.agent_id,
+      ...(value.parent_conversation_id ? { parentSessionId: value.parent_conversation_id } : {}),
+      state: state(value.status),
+      createdAt: value.created_at,
+      updatedAt: value.updated_at,
+    };
+  }
+}
+function state(value: string): RuntimeSessionState {
+  return (
+    (
+      { running: 'active', waiting: 'idle', starting: 'starting', stopped: 'stopped' } as Record<
+        string,
+        RuntimeSessionState
+      >
+    )[value] ?? 'failed'
+  );
+}

packages/agent/src/index.ts

@@ -2,4 +2,5 @@ export const VERSION = '0.0.0';
 
 export * from './runtime-provider-registry.js';
 export * from './tmux-fleet-runtime-provider.js';
+export * from './hermes-runtime-provider.js';
 export * from './tess-durable-session.js';