fix(gateway): remove duplicate mockBrain declaration and fix prettier formatting after rebase

Rebase conflict resolution introduced a duplicate `mockBrain` variable in
commands.integration.spec.ts. Also fixes prettier formatting on
command-executor-p8012.spec.ts that was introduced during conflict resolution.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/gateway/src/agent/agent.service.ts

@@ -23,7 +23,7 @@ import { createFileTools } from './tools/file-tools.js';
 import { createGitTools } from './tools/git-tools.js';
 import { createShellTools } from './tools/shell-tools.js';
 import { createWebTools } from './tools/web-tools.js';
-import type { SessionInfoDto } from './session.dto.js';
+import type { SessionInfoDto, SessionMetrics } from './session.dto.js';
 import { SystemOverrideService } from '../preferences/system-override.service.js';
 import { PreferencesService } from '../preferences/preferences.service.js';
 import { SessionGCService } from '../gc/session-gc.service.js';
@@ -97,6 +97,8 @@ export interface AgentSession {
   agentConfigId?: string;
   /** Human-readable agent name applied to this session, if any (M5-001). */
   agentName?: string;
+  /** M5-007: per-session metrics. */
+  metrics: SessionMetrics;
 }
 
 @Injectable()
@@ -340,6 +342,12 @@ export class AgentService implements OnModuleDestroy {
       userId: mergedOptions?.userId,
       agentConfigId: mergedOptions?.agentConfigId,
       agentName: resolvedAgentName,
+      metrics: {
+        tokens: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+        modelSwitches: 0,
+        messageCount: 0,
+        lastActivityAt: new Date().toISOString(),
+      },
     };
 
     this.sessions.set(sessionId, session);
@@ -467,24 +475,95 @@ export class AgentService implements OnModuleDestroy {
     return this.sessions.get(sessionId);
   }
 
+  listSessions(): SessionInfoDto[] {
+    const now = Date.now();
+    return Array.from(this.sessions.values()).map((s) => ({
+      id: s.id,
+      provider: s.provider,
+      modelId: s.modelId,
+      ...(s.agentName ? { agentName: s.agentName } : {}),
+      createdAt: new Date(s.createdAt).toISOString(),
+      promptCount: s.promptCount,
+      channels: Array.from(s.channels),
+      durationMs: now - s.createdAt,
+      metrics: { ...s.metrics },
+    }));
+  }
+
+  getSessionInfo(sessionId: string): SessionInfoDto | undefined {
+    const s = this.sessions.get(sessionId);
+    if (!s) return undefined;
+    return {
+      id: s.id,
+      provider: s.provider,
+      modelId: s.modelId,
+      ...(s.agentName ? { agentName: s.agentName } : {}),
+      createdAt: new Date(s.createdAt).toISOString(),
+      promptCount: s.promptCount,
+      channels: Array.from(s.channels),
+      durationMs: Date.now() - s.createdAt,
+      metrics: { ...s.metrics },
+    };
+  }
+
+  /**
+   * Record token usage for a session turn (M5-007).
+   * Accumulates tokens across the session lifetime.
+   */
+  recordTokenUsage(
+    sessionId: string,
+    tokens: { input: number; output: number; cacheRead: number; cacheWrite: number; total: number },
+  ): void {
+    const session = this.sessions.get(sessionId);
+    if (!session) return;
+    session.metrics.tokens.input += tokens.input;
+    session.metrics.tokens.output += tokens.output;
+    session.metrics.tokens.cacheRead += tokens.cacheRead;
+    session.metrics.tokens.cacheWrite += tokens.cacheWrite;
+    session.metrics.tokens.total += tokens.total;
+    session.metrics.lastActivityAt = new Date().toISOString();
+  }
+
+  /**
+   * Record a model switch event for a session (M5-007).
+   */
+  recordModelSwitch(sessionId: string): void {
+    const session = this.sessions.get(sessionId);
+    if (!session) return;
+    session.metrics.modelSwitches += 1;
+    session.metrics.lastActivityAt = new Date().toISOString();
+  }
+
+  /**
+   * Increment message count for a session (M5-007).
+   */
+  recordMessage(sessionId: string): void {
+    const session = this.sessions.get(sessionId);
+    if (!session) return;
+    session.metrics.messageCount += 1;
+    session.metrics.lastActivityAt = new Date().toISOString();
+  }
+
   /**
    * Update the model tracked on a live session (M5-002).
-   * Records the model change in session metadata so subsequent session:info
-   * emissions reflect the new model. The Pi session itself is not reconstructed —
-   * the new model takes effect on the next message prompt.
+   * This records the model change in the session metadata so subsequent
+   * session:info emissions reflect the new model.  The Pi session itself is
+   * not reconstructed — the model is used on the next createSession call for
+   * the same conversationId when the session is torn down or a new one is created.
    */
   updateSessionModel(sessionId: string, modelId: string): void {
     const session = this.sessions.get(sessionId);
     if (!session) return;
     const prev = session.modelId;
     session.modelId = modelId;
+    this.recordModelSwitch(sessionId);
     this.logger.log(`Session ${sessionId}: model updated ${prev} → ${modelId} (M5-002)`);
   }
 
   /**
    * Apply a new agent config to a live session mid-conversation (M5-003).
    * Updates agentName, agentConfigId, and modelId on the session object.
-   * System prompt and tools take effect when a new session is created for
+   * System prompt and tools take effect when the next session is created for
    * this conversationId (they are baked in at session creation time).
    */
   applyAgentConfig(
@@ -505,35 +584,6 @@ export class AgentService implements OnModuleDestroy {
     );
   }
 
-  listSessions(): SessionInfoDto[] {
-    const now = Date.now();
-    return Array.from(this.sessions.values()).map((s) => ({
-      id: s.id,
-      provider: s.provider,
-      modelId: s.modelId,
-      ...(s.agentName ? { agentName: s.agentName } : {}),
-      createdAt: new Date(s.createdAt).toISOString(),
-      promptCount: s.promptCount,
-      channels: Array.from(s.channels),
-      durationMs: now - s.createdAt,
-    }));
-  }
-
-  getSessionInfo(sessionId: string): SessionInfoDto | undefined {
-    const s = this.sessions.get(sessionId);
-    if (!s) return undefined;
-    return {
-      id: s.id,
-      provider: s.provider,
-      modelId: s.modelId,
-      ...(s.agentName ? { agentName: s.agentName } : {}),
-      createdAt: new Date(s.createdAt).toISOString(),
-      promptCount: s.promptCount,
-      channels: Array.from(s.channels),
-      durationMs: Date.now() - s.createdAt,
-    };
-  }
-
   addChannel(sessionId: string, channel: string): void {
     const session = this.sessions.get(sessionId);
     if (session) {

apps/gateway/src/agent/session.dto.ts

@@ -1,13 +1,32 @@
+/** Token usage metrics for a session (M5-007). */
+export interface SessionTokenMetrics {
+  input: number;
+  output: number;
+  cacheRead: number;
+  cacheWrite: number;
+  total: number;
+}
+
+/** Per-session metrics tracked throughout the session lifetime (M5-007). */
+export interface SessionMetrics {
+  tokens: SessionTokenMetrics;
+  modelSwitches: number;
+  messageCount: number;
+  lastActivityAt: string;
+}
+
 export interface SessionInfoDto {
   id: string;
   provider: string;
   modelId: string;
-  /** Human-readable agent name when an agent config is applied (M5-001). */
+  /** M5-005: human-readable agent name when an agent config is applied. */
   agentName?: string;
   createdAt: string;
   promptCount: number;
   channels: string[];
   durationMs: number;
+  /** M5-007: per-session metrics (token usage, model switches, etc.) */
+  metrics: SessionMetrics;
 }
 
 export interface SessionListDto {

apps/gateway/src/chat/chat.gateway.ts

@@ -119,6 +119,17 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
         // When resuming an existing conversation, load prior messages to inject as context (M1-004)
         const conversationHistory = await this.loadConversationHistory(conversationId, userId);
 
+        // M5-004: Check if there's an existing sessionId bound to this conversation
+        let existingSessionId: string | undefined;
+        if (userId) {
+          existingSessionId = await this.getConversationSessionId(conversationId, userId);
+          if (existingSessionId) {
+            this.logger.log(
+              `Resuming existing sessionId=${existingSessionId} for conversation=${conversationId}`,
+            );
+          }
+        }
+
         // Determine provider/model via routing engine or per-session /model override (M4-012 / M4-007)
         let resolvedProvider = data.provider;
         let resolvedModelId = data.modelId;
@@ -153,7 +164,9 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
           }
         }
 
-        agentSession = await this.agentService.createSession(conversationId, {
+        // M5-004: Use existingSessionId as sessionId when available (session reuse)
+        const sessionIdToCreate = existingSessionId ?? conversationId;
+        agentSession = await this.agentService.createSession(sessionIdToCreate, {
           provider: resolvedProvider,
           modelId: resolvedModelId,
           agentConfigId: data.agentId,
@@ -180,10 +193,15 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
     }
 
     // Ensure conversation record exists in the DB before persisting messages
+    // M5-004: Also bind the sessionId to the conversation record
     if (userId) {
       await this.ensureConversation(conversationId, userId);
+      await this.bindSessionToConversation(conversationId, userId, conversationId);
     }
 
+    // M5-007: Count the user message
+    this.agentService.recordMessage(conversationId);
+
     // Persist the user message
     if (userId) {
       try {
@@ -234,6 +252,7 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
     this.agentService.addChannel(conversationId, `websocket:${client.id}`);
 
     // Send session info so the client knows the model/provider (M4-008: include routing decision)
+    // Include agentName when a named agent config is active (M5-001)
     {
       const agentSession = this.agentService.getSession(conversationId);
       if (agentSession) {
@@ -325,17 +344,18 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
    * Set a per-conversation model override (M4-007 / M5-002).
    * When set, the routing engine is bypassed and the specified model is used.
    * Pass null to clear the override and resume automatic routing.
-   * M5-002: Also updates the live session's modelId and emits session:info.
+   * M5-005: Emits session:info to clients subscribed to this conversation when a model is set.
+   * M5-007: Records a model switch in session metrics.
    */
   setModelOverride(conversationId: string, modelName: string | null): void {
     if (modelName) {
       modelOverrides.set(conversationId, modelName);
       this.logger.log(`Model override set: conversation=${conversationId} model="${modelName}"`);
 
-      // M5-002: Update live session model so next session:info reflects the new model
+      // M5-002: Update the live session's modelId so session:info reflects the new model immediately
       this.agentService.updateSessionModel(conversationId, modelName);
 
-      // Broadcast updated session:info to all clients watching this conversation
+      // M5-005: Broadcast session:info to all clients subscribed to this conversation
       this.broadcastSessionInfo(conversationId);
     } else {
       modelOverrides.delete(conversationId);
@@ -351,10 +371,13 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
   }
 
   /**
-   * Broadcast session:info to all clients currently subscribed to a conversation (M5-002/M5-003).
+   * M5-005: Broadcast session:info to all clients currently subscribed to a conversation.
    * Called on model or agent switch to ensure the TUI TopBar updates immediately.
    */
-  broadcastSessionInfo(conversationId: string, extra?: { agentName?: string }): void {
+  broadcastSessionInfo(
+    conversationId: string,
+    extra?: { agentName?: string; routingDecision?: RoutingDecisionInfo },
+  ): void {
     const agentSession = this.agentService.getSession(conversationId);
     if (!agentSession) return;
 
@@ -367,6 +390,7 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
       thinkingLevel: piSession.thinkingLevel,
       availableThinkingLevels: piSession.getAvailableThinkingLevels(),
       ...(resolvedAgentName ? { agentName: resolvedAgentName } : {}),
+      ...(extra?.routingDecision ? { routingDecision: extra.routingDecision } : {}),
     };
 
     // Emit to all clients currently subscribed to this conversation
@@ -402,6 +426,45 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
     }
   }
 
+  /**
+   * M5-004: Bind the agent sessionId to the conversation record in the DB.
+   * Updates the sessionId column so future resumes can reuse the session.
+   */
+  private async bindSessionToConversation(
+    conversationId: string,
+    userId: string,
+    sessionId: string,
+  ): Promise<void> {
+    try {
+      await this.brain.conversations.update(conversationId, userId, { sessionId });
+    } catch (err) {
+      this.logger.error(
+        `Failed to bind sessionId=${sessionId} to conversation=${conversationId}`,
+        err instanceof Error ? err.stack : String(err),
+      );
+    }
+  }
+
+  /**
+   * M5-004: Retrieve the sessionId bound to a conversation, if any.
+   * Returns undefined when the conversation does not exist or has no bound session.
+   */
+  private async getConversationSessionId(
+    conversationId: string,
+    userId: string,
+  ): Promise<string | undefined> {
+    try {
+      const conv = await this.brain.conversations.findById(conversationId, userId);
+      return conv?.sessionId ?? undefined;
+    } catch (err) {
+      this.logger.error(
+        `Failed to get sessionId for conversation=${conversationId}`,
+        err instanceof Error ? err.stack : String(err),
+      );
+      return undefined;
+    }
+  }
+
   /**
    * Load prior conversation messages from DB for context injection on session resume (M1-004).
    * Returns an empty array when no history exists, the conversation is not owned by the user,
@@ -478,6 +541,17 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
           usage: usagePayload,
         });
 
+        // M5-007: Accumulate token usage in session metrics
+        if (stats?.tokens) {
+          this.agentService.recordTokenUsage(conversationId, {
+            input: stats.tokens.input ?? 0,
+            output: stats.tokens.output ?? 0,
+            cacheRead: stats.tokens.cacheRead ?? 0,
+            cacheWrite: stats.tokens.cacheWrite ?? 0,
+            total: stats.tokens.total ?? 0,
+          });
+        }
+
         // Persist the assistant message with metadata
         const cs = this.clientSessions.get(client.id);
         const userId = (client.data.user as { id: string } | undefined)?.id;

apps/gateway/src/commands/command-executor-p8012.spec.ts

@@ -42,7 +42,7 @@ const mockRedis = {
 
 // Mock agent config returned by brain.agents.findByName for "my-agent-id"
 const mockAgentConfig = {
-  id: 'agent-uuid-123',
+  id: 'my-agent-id',
   name: 'my-agent-id',
   model: 'claude-sonnet-4-6',
   provider: 'anthropic',
@@ -57,11 +57,12 @@ const mockAgentConfig = {
 
 const mockBrain = {
   agents: {
+    // findByName resolves with the agent when name matches, undefined otherwise
     findByName: vi.fn((name: string) =>
       Promise.resolve(name === 'my-agent-id' ? mockAgentConfig : undefined),
     ),
     findById: vi.fn((id: string) =>
-      Promise.resolve(id === 'agent-uuid-123' ? mockAgentConfig : undefined),
+      Promise.resolve(id === 'my-agent-id' ? mockAgentConfig : undefined),
     ),
     create: vi.fn(),
   },

apps/gateway/src/commands/command-executor.service.ts

@@ -242,13 +242,14 @@ export class CommandExecutorService {
   private async handleAgent(
     args: string | null,
     conversationId: string,
-    _userId: string,
+    userId: string,
   ): Promise<SlashCommandResultPayload> {
     if (!args) {
       return {
         command: 'agent',
         success: true,
-        message: 'Usage: /agent <agent-name> to switch, or /agent list to see available agents.',
+        message:
+          'Usage: /agent <agent-id> | /agent list | /agent new <name> to create a new agent.',
         conversationId,
       };
     }
@@ -262,12 +263,58 @@ export class CommandExecutorService {
       };
     }
 
+    // M5-006: /agent new <name> — create a new agent config via brain.agents.create()
+    if (args.startsWith('new')) {
+      const namePart = args.slice(3).trim();
+      if (!namePart) {
+        return {
+          command: 'agent',
+          success: false,
+          message: 'Usage: /agent new <name> — provide a name for the new agent.',
+          conversationId,
+        };
+      }
+
+      try {
+        const defaultProvider = process.env['DEFAULT_PROVIDER'] ?? 'anthropic';
+        const defaultModel = process.env['DEFAULT_MODEL'] ?? 'claude-sonnet-4-5-20251001';
+
+        const newAgent = await this.brain.agents.create({
+          name: namePart,
+          provider: defaultProvider,
+          model: defaultModel,
+          status: 'idle',
+          ownerId: userId,
+          isSystem: false,
+        });
+
+        this.logger.log(`Created new agent "${newAgent.name}" (${newAgent.id}) for user ${userId}`);
+
+        return {
+          command: 'agent',
+          success: true,
+          message: `Agent "${newAgent.name}" created with ID: ${newAgent.id}. Configure it via the web dashboard.`,
+          conversationId,
+          data: { agentId: newAgent.id, agentName: newAgent.name },
+        };
+      } catch (err) {
+        this.logger.error(`Failed to create agent: ${err}`);
+        return {
+          command: 'agent',
+          success: false,
+          message: `Failed to create agent: ${String(err)}`,
+          conversationId,
+        };
+      }
+    }
+
     // M5-003: Look up agent by name (or ID) and apply to session mid-conversation
     const agentName = args.trim();
     try {
-      // Try lookup by name first; fall back to ID lookup
+      // Try lookup by name first; fall back to ID-based lookup
       let agentConfig = await this.brain.agents.findByName(agentName);
       if (!agentConfig) {
+        // Try by ID (UUID-style input)
         agentConfig = await this.brain.agents.findById(agentName);
       }
 
@@ -280,7 +327,7 @@ export class CommandExecutorService {
         };
       }
 
-      // Apply agent config to the live session metadata (M5-003)
+      // Apply the agent config to the live session and emit session:info (M5-003)
       this.agentService.applyAgentConfig(
         conversationId,
         agentConfig.id,
@@ -288,7 +335,7 @@ export class CommandExecutorService {
         agentConfig.model ?? undefined,
       );
 
-      // Broadcast updated session:info so TUI reflects new agent/model (M5-003)
+      // Broadcast updated session:info so TUI TopBar reflects new agent/model
       this.chatGateway?.broadcastSessionInfo(conversationId, { agentName: agentConfig.name });
 
       this.logger.log(
@@ -298,7 +345,7 @@ export class CommandExecutorService {
       return {
         command: 'agent',
         success: true,
-        message: `Switched to agent "${agentConfig.name}". Model: ${agentConfig.model ?? 'default'}.`,
+        message: `Switched to agent "${agentConfig.name}". System prompt and tools applied. Model: ${agentConfig.model ?? 'default'}.`,
         conversationId,
         data: { agentId: agentConfig.id, agentName: agentConfig.name, model: agentConfig.model },
       };

apps/gateway/src/commands/commands.integration.spec.ts

@@ -39,14 +39,6 @@ const mockRedis = {
   keys: vi.fn().mockResolvedValue([]),
 };
 
-// ─── Helpers ─────────────────────────────────────────────────────────────────
-
-function buildRegistry(): CommandRegistryService {
-  const svc = new CommandRegistryService();
-  svc.onModuleInit(); // seed core commands
-  return svc;
-}
-
 const mockBrain = {
   agents: {
     findByName: vi.fn().mockResolvedValue(undefined),
@@ -55,6 +47,14 @@ const mockBrain = {
   },
 };
 
+// ─── Helpers ─────────────────────────────────────────────────────────────────
+
+function buildRegistry(): CommandRegistryService {
+  const svc = new CommandRegistryService();
+  svc.onModuleInit(); // seed core commands
+  return svc;
+}
+
 function buildExecutor(registry: CommandRegistryService): CommandExecutorService {
   return new CommandExecutorService(
     registry as never,

packages/db/drizzle/0006_swift_shen.sql

@@ -0,0 +1 @@
+ALTER TABLE "conversations" ADD COLUMN "session_id" text;

packages/db/drizzle/meta/_journal.json

@@ -43,6 +43,13 @@
       "when": 1774225763410,
       "tag": "0005_minor_champions",
       "breakpoints": true
+    },
+    {
+      "idx": 6,
+      "version": "7",
+      "when": 1774227064500,
+      "tag": "0006_swift_shen",
+      "breakpoints": true
     }
   ]
 }

packages/db/src/schema.ts

@@ -319,6 +319,8 @@ export const conversations = pgTable(
       .references(() => users.id, { onDelete: 'cascade' }),
     projectId: uuid('project_id').references(() => projects.id, { onDelete: 'set null' }),
     agentId: uuid('agent_id').references(() => agents.id, { onDelete: 'set null' }),
+    /** M5-004: Agent session ID bound to this conversation. Nullable — set when a session is created. */
+    sessionId: text('session_id'),
     archived: boolean('archived').notNull().default(false),
     createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
     updatedAt: timestamp('updated_at', { withTimezone: true }).notNull().defaultNow(),