feat(agent): add transitional Hermes runtime adapter (#734)

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'
+  );
+}