diff --git a/apps/gateway/package.json b/apps/gateway/package.json
index 1a2cb97..8e5819f 100644
--- a/apps/gateway/package.json
+++ b/apps/gateway/package.json
@@ -31,6 +31,7 @@
     "@mariozechner/pi-ai": "^0.65.0",
     "@mariozechner/pi-coding-agent": "^0.65.0",
     "@modelcontextprotocol/sdk": "^1.27.1",
+    "@mosaicstack/agent": "workspace:^",
     "@mosaicstack/auth": "workspace:^",
     "@mosaicstack/brain": "workspace:^",
     "@mosaicstack/config": "workspace:^",
diff --git a/apps/gateway/src/agent/__tests__/runtime-provider-registry.service.test.ts b/apps/gateway/src/agent/__tests__/runtime-provider-registry.service.test.ts
new file mode 100644
index 0000000..8541554
--- /dev/null
+++ b/apps/gateway/src/agent/__tests__/runtime-provider-registry.service.test.ts
@@ -0,0 +1,285 @@
+import { describe, expect, it } from 'vitest';
+import type {
+  AgentRuntimeProvider,
+  RuntimeAttachHandle,
+  RuntimeAttachMode,
+  RuntimeCapability,
+  RuntimeCapabilitySet,
+  RuntimeHealth,
+  RuntimeMessage,
+  RuntimeScope,
+  RuntimeSession,
+  RuntimeSessionTree,
+  RuntimeStreamEvent,
+} from '@mosaicstack/types';
+import { AgentRuntimeProviderRegistry } from '@mosaicstack/agent';
+import type { ActorTenantScope } from '../../auth/session-scope.js';
+import {
+  RuntimeProviderService,
+  type RuntimeAuditEvent,
+  type RuntimeAuditSink,
+  type RuntimeApprovalVerifier,
+} from '../runtime-provider-registry.service.js';
+
+const OWNER_SCOPE: ActorTenantScope = { userId: 'owner-1', tenantId: 'tenant-1' };
+const CONTEXT = {
+  actorScope: OWNER_SCOPE,
+  channelId: 'cli',
+  correlationId: 'correlation-1',
+};
+
+class RecordingRuntimeProvider implements AgentRuntimeProvider {
+  readonly id = 'fleet';
+  readonly receivedScopes: RuntimeScope[] = [];
+  readonly sentMessages: RuntimeMessage[] = [];
+  terminateCalls = 0;
+  throwAfterSend = false;
+
+  constructor(private readonly supported: RuntimeCapability[]) {}
+
+  async capabilities(scope: RuntimeScope): Promise<RuntimeCapabilitySet> {
+    this.receivedScopes.push(scope);
+    return { supported: this.supported };
+  }
+
+  async health(scope: RuntimeScope): Promise<RuntimeHealth> {
+    this.receivedScopes.push(scope);
+    return { status: 'healthy', checkedAt: '2026-07-12T00:00:00.000Z' };
+  }
+
+  async listSessions(scope: RuntimeScope): Promise<RuntimeSession[]> {
+    this.receivedScopes.push(scope);
+    return [];
+  }
+
+  async getSessionTree(scope: RuntimeScope): Promise<RuntimeSessionTree[]> {
+    this.receivedScopes.push(scope);
+    return [];
+  }
+
+  async *streamSession(
+    _sessionId: string,
+    _cursor: string | undefined,
+    scope: RuntimeScope,
+  ): AsyncIterable<RuntimeStreamEvent> {
+    this.receivedScopes.push(scope);
+    return;
+  }
+
+  async sendMessage(
+    _sessionId: string,
+    message: RuntimeMessage,
+    scope: RuntimeScope,
+  ): Promise<void> {
+    this.receivedScopes.push(scope);
+    this.sentMessages.push(message);
+    if (this.throwAfterSend) {
+      throw new Error('provider acknowledgement failed');
+    }
+  }
+
+  async attach(
+    sessionId: string,
+    mode: RuntimeAttachMode,
+    scope: RuntimeScope,
+  ): Promise<RuntimeAttachHandle> {
+    this.receivedScopes.push(scope);
+    return {
+      attachmentId: 'attachment-1',
+      sessionId,
+      mode,
+      expiresAt: '2026-07-12T00:00:00.000Z',
+    };
+  }
+
+  async detach(_attachmentId: string, scope: RuntimeScope): Promise<void> {
+    this.receivedScopes.push(scope);
+  }
+
+  async terminate(_sessionId: string, _approvalRef: string, scope: RuntimeScope): Promise<void> {
+    this.receivedScopes.push(scope);
+    this.terminateCalls += 1;
+  }
+}
+
+class RecordingAuditSink implements RuntimeAuditSink {
+  readonly events: RuntimeAuditEvent[] = [];
+
+  async record(event: RuntimeAuditEvent): Promise<void> {
+    this.events.push(event);
+  }
+}
+
+class DenyingApprovalVerifier implements RuntimeApprovalVerifier {
+  async consume(): Promise<boolean> {
+    return false;
+  }
+}
+
+class AcceptingApprovalVerifier implements RuntimeApprovalVerifier {
+  consumedAction: Parameters<RuntimeApprovalVerifier['consume']>[1] | undefined;
+
+  async consume(
+    _approvalRef: string,
+    action: Parameters<RuntimeApprovalVerifier['consume']>[1],
+  ): Promise<boolean> {
+    this.consumedAction = action;
+    return true;
+  }
+}
+
+function makeService(
+  provider: RecordingRuntimeProvider,
+  audit: RuntimeAuditSink = new RecordingAuditSink(),
+  approval: RuntimeApprovalVerifier = new DenyingApprovalVerifier(),
+): RuntimeProviderService {
+  const registry = new AgentRuntimeProviderRegistry();
+  registry.register(provider);
+  return new RuntimeProviderService(registry, audit, approval);
+}
+
+describe('RuntimeProviderService security boundary', (): void => {
+  it('derives and freezes only the authenticated actor scope while preserving correlation metadata', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.send']);
+    const audit = new RecordingAuditSink();
+    const service = makeService(provider, audit);
+
+    await service.sendMessage(
+      'fleet',
+      'session-1',
+      { content: 'hello', idempotencyKey: 'key-1' },
+      CONTEXT,
+    );
+
+    const providerScope = provider.receivedScopes[0];
+    expect(providerScope).toEqual({
+      actorId: OWNER_SCOPE.userId,
+      tenantId: OWNER_SCOPE.tenantId,
+      channelId: CONTEXT.channelId,
+      correlationId: CONTEXT.correlationId,
+    });
+    expect(Object.isFrozen(providerScope)).toBe(true);
+    expect(audit.events).toContainEqual({
+      providerId: 'fleet',
+      operation: 'session.send',
+      outcome: 'succeeded',
+      actorId: OWNER_SCOPE.userId,
+      tenantId: OWNER_SCOPE.tenantId,
+      channelId: CONTEXT.channelId,
+      correlationId: CONTEXT.correlationId,
+      resourceId: 'session-1',
+    });
+    expect(JSON.stringify(audit.events)).not.toContain('hello');
+    expect(JSON.stringify(audit.events)).not.toContain('key-1');
+  });
+
+  it('fails closed before a provider side effect when a capability is missing', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider([]);
+    const service = makeService(provider);
+
+    await expect(
+      service.sendMessage(
+        'fleet',
+        'session-1',
+        { content: 'hello', idempotencyKey: 'key-1' },
+        CONTEXT,
+      ),
+    ).rejects.toThrow(/capability denied/);
+    expect(provider.sentMessages).toEqual([]);
+  });
+
+  it('requires a consumed exact-action approval before termination', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.terminate']);
+    const approval = new DenyingApprovalVerifier();
+    const service = makeService(provider, new RecordingAuditSink(), approval);
+
+    await expect(
+      service.terminate('fleet', 'session-1', 'forged-approval', CONTEXT),
+    ).rejects.toThrow(/approval denied/);
+    expect(provider.terminateCalls).toBe(0);
+  });
+
+  it('binds an accepted termination approval to provider, session, immutable scope, and correlation', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.terminate']);
+    const approval = new AcceptingApprovalVerifier();
+    const service = makeService(provider, new RecordingAuditSink(), approval);
+
+    await service.terminate('fleet', 'session-1', 'approval-1', CONTEXT);
+
+    expect(approval.consumedAction).toEqual({
+      providerId: 'fleet',
+      sessionId: 'session-1',
+      actorId: OWNER_SCOPE.userId,
+      tenantId: OWNER_SCOPE.tenantId,
+      channelId: CONTEXT.channelId,
+      correlationId: CONTEXT.correlationId,
+    });
+    expect(provider.terminateCalls).toBe(1);
+  });
+
+  it('fails closed before invoking a provider when audit persistence rejects the request', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.send']);
+    const unavailableAudit: RuntimeAuditSink = {
+      async record(): Promise<void> {
+        throw new Error('audit unavailable');
+      },
+    };
+    const service = makeService(provider, unavailableAudit);
+
+    await expect(
+      service.sendMessage(
+        'fleet',
+        'session-1',
+        { content: 'hello', idempotencyKey: 'key-1' },
+        CONTEXT,
+      ),
+    ).rejects.toThrow(/audit unavailable/);
+    expect(provider.sentMessages).toEqual([]);
+  });
+
+  it('records a provider error after invocation as failed rather than denied', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.send']);
+    provider.throwAfterSend = true;
+    const audit = new RecordingAuditSink();
+    const service = makeService(provider, audit);
+
+    await expect(
+      service.sendMessage(
+        'fleet',
+        'session-1',
+        { content: 'hello', idempotencyKey: 'key-1' },
+        CONTEXT,
+      ),
+    ).rejects.toThrow(/provider acknowledgement failed/);
+    expect(provider.sentMessages).toHaveLength(1);
+    expect(audit.events.map((event: RuntimeAuditEvent): string => event.outcome)).toEqual([
+      'requested',
+      'failed',
+    ]);
+  });
+
+  it('does not misreport a completed provider side effect when completion auditing fails', async (): Promise<void> => {
+    const provider = new RecordingRuntimeProvider(['session.send']);
+    let auditCalls = 0;
+    const audit: RuntimeAuditSink = {
+      async record(): Promise<void> {
+        auditCalls += 1;
+        if (auditCalls === 2) {
+          throw new Error('completion audit unavailable');
+        }
+      },
+    };
+    const service = makeService(provider, audit);
+
+    await expect(
+      service.sendMessage(
+        'fleet',
+        'session-1',
+        { content: 'hello', idempotencyKey: 'key-1' },
+        CONTEXT,
+      ),
+    ).resolves.toBeUndefined();
+    expect(provider.sentMessages).toHaveLength(1);
+    expect(auditCalls).toBe(2);
+  });
+});
diff --git a/apps/gateway/src/agent/agent.module.ts b/apps/gateway/src/agent/agent.module.ts
index 94b9fa3..3d789ae 100644
--- a/apps/gateway/src/agent/agent.module.ts
+++ b/apps/gateway/src/agent/agent.module.ts
@@ -1,4 +1,5 @@
 import { Global, Module } from '@nestjs/common';
+import { AgentRuntimeProviderRegistry } from '@mosaicstack/agent';
 import { AgentService } from './agent.service.js';
 import { ProviderService } from './provider.service.js';
 import { ProviderCredentialsService } from './provider-credentials.service.js';
@@ -13,6 +14,14 @@ import { CoordModule } from '../coord/coord.module.js';
 import { McpClientModule } from '../mcp-client/mcp-client.module.js';
 import { SkillsModule } from '../skills/skills.module.js';
 import { GCModule } from '../gc/gc.module.js';
+import {
+  AGENT_RUNTIME_PROVIDER_REGISTRY,
+  DenyRuntimeApprovalVerifier,
+  RUNTIME_APPROVAL_VERIFIER,
+  RUNTIME_PROVIDER_AUDIT_SINK,
+  RuntimeProviderAuditService,
+  RuntimeProviderService,
+} from './runtime-provider-registry.service.js';
 
 @Global()
 @Module({
@@ -23,6 +32,21 @@ import { GCModule } from '../gc/gc.module.js';
     RoutingService,
     RoutingEngineService,
     SkillLoaderService,
+    {
+      provide: AGENT_RUNTIME_PROVIDER_REGISTRY,
+      useFactory: (): AgentRuntimeProviderRegistry => new AgentRuntimeProviderRegistry(),
+    },
+    RuntimeProviderAuditService,
+    {
+      provide: RUNTIME_PROVIDER_AUDIT_SINK,
+      useExisting: RuntimeProviderAuditService,
+    },
+    DenyRuntimeApprovalVerifier,
+    {
+      provide: RUNTIME_APPROVAL_VERIFIER,
+      useExisting: DenyRuntimeApprovalVerifier,
+    },
+    RuntimeProviderService,
     AgentService,
   ],
   controllers: [ProvidersController, SessionsController, AgentConfigsController, RoutingController],
@@ -33,6 +57,8 @@ import { GCModule } from '../gc/gc.module.js';
     RoutingService,
     RoutingEngineService,
     SkillLoaderService,
+    RuntimeProviderService,
+    AGENT_RUNTIME_PROVIDER_REGISTRY,
   ],
 })
 export class AgentModule {}
diff --git a/apps/gateway/src/agent/runtime-provider-registry.service.ts b/apps/gateway/src/agent/runtime-provider-registry.service.ts
new file mode 100644
index 0000000..89617e5
--- /dev/null
+++ b/apps/gateway/src/agent/runtime-provider-registry.service.ts
@@ -0,0 +1,404 @@
+import { ForbiddenException, Inject, Injectable, Logger, NotFoundException } from '@nestjs/common';
+import { AgentRuntimeProviderRegistry } from '@mosaicstack/agent';
+import type {
+  AgentRuntimeProvider,
+  RuntimeAttachHandle,
+  RuntimeAttachMode,
+  RuntimeCapability,
+  RuntimeCapabilitySet,
+  RuntimeHealth,
+  RuntimeMessage,
+  RuntimeScope,
+  RuntimeSession,
+  RuntimeSessionTree,
+  RuntimeStreamEvent,
+} from '@mosaicstack/types';
+import type { ActorTenantScope } from '../auth/session-scope.js';
+
+export const AGENT_RUNTIME_PROVIDER_REGISTRY = Symbol('AGENT_RUNTIME_PROVIDER_REGISTRY');
+export const RUNTIME_PROVIDER_AUDIT_SINK = Symbol('RUNTIME_PROVIDER_AUDIT_SINK');
+export const RUNTIME_APPROVAL_VERIFIER = Symbol('RUNTIME_APPROVAL_VERIFIER');
+
+export type RuntimeProviderOperation =
+  | RuntimeCapability
+  | 'runtime.capabilities'
+  | 'runtime.health';
+export type RuntimeProviderAuditOutcome = 'requested' | 'succeeded' | 'denied' | 'failed';
+
+/** Trusted server-side context only; it intentionally excludes client-provided identity fields. */
+export interface RuntimeProviderRequestContext {
+  actorScope: ActorTenantScope;
+  channelId: string;
+  correlationId: string;
+}
+
+/** Metadata-only audit record. Message bodies, idempotency keys, and approval refs are excluded. */
+export interface RuntimeAuditEvent {
+  providerId: string;
+  operation: RuntimeProviderOperation;
+  outcome: RuntimeProviderAuditOutcome;
+  actorId: string;
+  tenantId: string;
+  channelId: string;
+  correlationId: string;
+  resourceId?: string;
+}
+
+export interface RuntimeAuditSink {
+  record(event: RuntimeAuditEvent): Promise<void>;
+}
+
+/** Exact action shape that a durable approval implementation must consume once. */
+export interface RuntimeTerminationAction {
+  providerId: string;
+  sessionId: string;
+  actorId: string;
+  tenantId: string;
+  channelId: string;
+  correlationId: string;
+}
+
+export interface RuntimeApprovalVerifier {
+  consume(approvalRef: string, action: RuntimeTerminationAction): Promise<boolean>;
+}
+
+class RuntimeApprovalDeniedError extends Error {
+  constructor() {
+    super('Runtime termination approval denied');
+  }
+}
+
+/**
+ * The default denies all runtime termination until a durable, exact-action
+ * approval implementation is configured. This is safer than a permissive stub.
+ */
+@Injectable()
+export class DenyRuntimeApprovalVerifier implements RuntimeApprovalVerifier {
+  async consume(_approvalRef: string, _action: RuntimeTerminationAction): Promise<boolean> {
+    return false;
+  }
+}
+
+/**
+ * Temporary metadata-only audit sink. M1 observability can replace this token
+ * with a durable audit writer without changing provider call sites.
+ */
+@Injectable()
+export class RuntimeProviderAuditService implements RuntimeAuditSink {
+  private readonly logger = new Logger(RuntimeProviderAuditService.name);
+
+  async record(event: RuntimeAuditEvent): Promise<void> {
+    this.logger.log(JSON.stringify(event));
+  }
+}
+
+@Injectable()
+export class RuntimeProviderService {
+  private readonly logger = new Logger(RuntimeProviderService.name);
+
+  constructor(
+    @Inject(AGENT_RUNTIME_PROVIDER_REGISTRY)
+    private readonly registry: AgentRuntimeProviderRegistry,
+    @Inject(RUNTIME_PROVIDER_AUDIT_SINK)
+    private readonly audit: RuntimeAuditSink,
+    @Inject(RUNTIME_APPROVAL_VERIFIER)
+    private readonly approvals: RuntimeApprovalVerifier,
+  ) {}
+
+  async capabilities(
+    providerId: string,
+    context: RuntimeProviderRequestContext,
+  ): Promise<RuntimeCapabilitySet> {
+    return this.execute(
+      providerId,
+      'runtime.capabilities',
+      undefined,
+      undefined,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<RuntimeCapabilitySet> =>
+        provider.capabilities(scope),
+    );
+  }
+
+  async health(providerId: string, context: RuntimeProviderRequestContext): Promise<RuntimeHealth> {
+    return this.execute(
+      providerId,
+      'runtime.health',
+      undefined,
+      undefined,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<RuntimeHealth> =>
+        provider.health(scope),
+    );
+  }
+
+  async listSessions(
+    providerId: string,
+    context: RuntimeProviderRequestContext,
+  ): Promise<RuntimeSession[]> {
+    return this.execute(
+      providerId,
+      'session.list',
+      'session.list',
+      undefined,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<RuntimeSession[]> =>
+        provider.listSessions(scope),
+    );
+  }
+
+  async getSessionTree(
+    providerId: string,
+    context: RuntimeProviderRequestContext,
+  ): Promise<RuntimeSessionTree[]> {
+    return this.execute(
+      providerId,
+      'session.tree',
+      'session.tree',
+      undefined,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<RuntimeSessionTree[]> =>
+        provider.getSessionTree(scope),
+    );
+  }
+
+  streamSession(
+    providerId: string,
+    sessionId: string,
+    cursor: string | undefined,
+    context: RuntimeProviderRequestContext,
+  ): AsyncIterable<RuntimeStreamEvent> {
+    return this.stream(
+      providerId,
+      'session.stream',
+      'session.stream',
+      sessionId,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): AsyncIterable<RuntimeStreamEvent> =>
+        provider.streamSession(sessionId, cursor, scope),
+    );
+  }
+
+  async sendMessage(
+    providerId: string,
+    sessionId: string,
+    message: RuntimeMessage,
+    context: RuntimeProviderRequestContext,
+  ): Promise<void> {
+    await this.execute(
+      providerId,
+      'session.send',
+      'session.send',
+      sessionId,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<void> =>
+        provider.sendMessage(sessionId, message, scope),
+    );
+  }
+
+  async attach(
+    providerId: string,
+    sessionId: string,
+    mode: RuntimeAttachMode,
+    context: RuntimeProviderRequestContext,
+  ): Promise<RuntimeAttachHandle> {
+    return this.execute(
+      providerId,
+      'session.attach',
+      'session.attach',
+      sessionId,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<RuntimeAttachHandle> =>
+        provider.attach(sessionId, mode, scope),
+    );
+  }
+
+  async detach(
+    providerId: string,
+    attachmentId: string,
+    context: RuntimeProviderRequestContext,
+  ): Promise<void> {
+    await this.execute(
+      providerId,
+      'session.attach',
+      'session.attach',
+      attachmentId,
+      context,
+      (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<void> =>
+        provider.detach(attachmentId, scope),
+    );
+  }
+
+  async terminate(
+    providerId: string,
+    sessionId: string,
+    approvalRef: string,
+    context: RuntimeProviderRequestContext,
+  ): Promise<void> {
+    await this.execute(
+      providerId,
+      'session.terminate',
+      'session.terminate',
+      sessionId,
+      context,
+      async (provider: AgentRuntimeProvider, scope: RuntimeScope): Promise<void> => {
+        const approved = await this.approvals.consume(approvalRef, {
+          providerId,
+          sessionId,
+          actorId: scope.actorId,
+          tenantId: scope.tenantId,
+          channelId: scope.channelId,
+          correlationId: scope.correlationId,
+        });
+        if (!approved) {
+          throw new RuntimeApprovalDeniedError();
+        }
+        await provider.terminate(sessionId, approvalRef, scope);
+      },
+    );
+  }
+
+  private async execute<T>(
+    providerId: string,
+    operation: RuntimeProviderOperation,
+    requiredCapability: RuntimeCapability | undefined,
+    resourceId: string | undefined,
+    context: RuntimeProviderRequestContext,
+    invoke: (provider: AgentRuntimeProvider, scope: RuntimeScope) => Promise<T>,
+  ): Promise<T> {
+    const scope = this.deriveScope(context);
+    await this.record(providerId, operation, 'requested', scope, resourceId);
+    let invocationStarted = false;
+    try {
+      const provider = this.provider(providerId);
+      if (requiredCapability) {
+        await this.assertCapability(provider, requiredCapability, scope);
+      }
+      invocationStarted = true;
+      const result = await invoke(provider, scope);
+      await this.recordCompletion(providerId, operation, scope, resourceId);
+      return result;
+    } catch (error: unknown) {
+      if (invocationStarted && !(error instanceof RuntimeApprovalDeniedError)) {
+        await this.recordFailure(providerId, operation, scope, resourceId);
+      } else {
+        await this.record(providerId, operation, 'denied', scope, resourceId);
+      }
+      throw error;
+    }
+  }
+
+  private async *stream(
+    providerId: string,
+    operation: RuntimeProviderOperation,
+    requiredCapability: RuntimeCapability,
+    resourceId: string,
+    context: RuntimeProviderRequestContext,
+    invoke: (
+      provider: AgentRuntimeProvider,
+      scope: RuntimeScope,
+    ) => AsyncIterable<RuntimeStreamEvent>,
+  ): AsyncIterable<RuntimeStreamEvent> {
+    const scope = this.deriveScope(context);
+    await this.record(providerId, operation, 'requested', scope, resourceId);
+    let invocationStarted = false;
+    try {
+      const provider = this.provider(providerId);
+      await this.assertCapability(provider, requiredCapability, scope);
+      invocationStarted = true;
+      for await (const event of invoke(provider, scope)) {
+        yield event;
+      }
+      await this.recordCompletion(providerId, operation, scope, resourceId);
+    } catch (error: unknown) {
+      if (invocationStarted) {
+        await this.recordFailure(providerId, operation, scope, resourceId);
+      } else {
+        await this.record(providerId, operation, 'denied', scope, resourceId);
+      }
+      throw error;
+    }
+  }
+
+  private provider(providerId: string): AgentRuntimeProvider {
+    try {
+      return this.registry.require(providerId);
+    } catch (error: unknown) {
+      const message = error instanceof Error ? error.message : 'Runtime provider is not registered';
+      throw new NotFoundException(message);
+    }
+  }
+
+  private async assertCapability(
+    provider: AgentRuntimeProvider,
+    requiredCapability: RuntimeCapability,
+    scope: RuntimeScope,
+  ): Promise<void> {
+    const capabilities = await provider.capabilities(scope);
+    if (!capabilities.supported.includes(requiredCapability)) {
+      throw new ForbiddenException(`Runtime provider capability denied: ${requiredCapability}`);
+    }
+  }
+
+  private deriveScope(context: RuntimeProviderRequestContext): RuntimeScope {
+    const actorId = context.actorScope.userId.trim();
+    const tenantId = context.actorScope.tenantId.trim();
+    const channelId = context.channelId.trim();
+    const correlationId = context.correlationId.trim();
+    if (!actorId || !tenantId || !channelId || !correlationId) {
+      throw new ForbiddenException(
+        'Authenticated runtime actor scope and correlation are required',
+      );
+    }
+    return Object.freeze({ actorId, tenantId, channelId, correlationId });
+  }
+
+  private async recordFailure(
+    providerId: string,
+    operation: RuntimeProviderOperation,
+    scope: RuntimeScope,
+    resourceId: string | undefined,
+  ): Promise<void> {
+    try {
+      await this.record(providerId, operation, 'failed', scope, resourceId);
+    } catch {
+      this.logger.error(
+        `Runtime provider failure audit failed provider=${providerId} operation=${operation} correlation=${scope.correlationId}`,
+      );
+    }
+  }
+
+  private async recordCompletion(
+    providerId: string,
+    operation: RuntimeProviderOperation,
+    scope: RuntimeScope,
+    resourceId: string | undefined,
+  ): Promise<void> {
+    try {
+      await this.record(providerId, operation, 'succeeded', scope, resourceId);
+    } catch {
+      this.logger.error(
+        `Runtime provider completion audit failed provider=${providerId} operation=${operation} correlation=${scope.correlationId}`,
+      );
+    }
+  }
+
+  private async record(
+    providerId: string,
+    operation: RuntimeProviderOperation,
+    outcome: RuntimeProviderAuditOutcome,
+    scope: RuntimeScope,
+    resourceId: string | undefined,
+  ): Promise<void> {
+    await this.audit.record({
+      providerId,
+      operation,
+      outcome,
+      actorId: scope.actorId,
+      tenantId: scope.tenantId,
+      channelId: scope.channelId,
+      correlationId: scope.correlationId,
+      ...(resourceId ? { resourceId } : {}),
+    });
+  }
+}
diff --git a/docs/scratchpads/tess-m1-002-provider-registry.md b/docs/scratchpads/tess-m1-002-provider-registry.md
new file mode 100644
index 0000000..f9d6c67
--- /dev/null
+++ b/docs/scratchpads/tess-m1-002-provider-registry.md
@@ -0,0 +1,38 @@
+# TESS-M1-002 — Provider Registry
+
+- **Issue:** #707
+- **Branch:** `feat/tess-provider-registry`
+- **Objective:** Build the runtime provider registry/service boundary that derives immutable actor/tenant/channel/correlation scope server-side, fail-closes unsupported and destructive runtime operations, binds termination approval to the exact structured action, and emits correlation-safe audit events.
+
+## Plan
+
+1. Add a provider-agnostic registry in `@mosaicstack/agent` over the merged `AgentRuntimeProvider` contract.
+2. Write abuse-case tests before implementation for duplicate/unknown providers, immutable server-derived scope, capability denial, approval mismatch/absence, and audit failure.
+3. Implement the Gateway service that converts only authenticated `ActorTenantScope` plus trusted ingress metadata into a frozen `RuntimeScope`, gates capabilities and terminate approval, and records metadata-only audits.
+4. Register the service in `AgentModule`, then run focused, baseline, cold-cache, and independent-review gates.
+
+## Security Invariants
+
+- Caller-supplied actor/tenant identity never reaches runtime providers.
+- Provider capability absence and approval/audit failure deny before side effects.
+- Termination approval is verified against provider, session, actor, tenant, channel, and correlation context.
+- Audit events retain correlation and authority metadata but never message content or approval material.
+
+## Progress
+
+- 2026-07-12: Created fresh worktree from `origin/main` at `119f64e6`; source and Tess planning/security documentation reviewed.
+- 2026-07-12: Security TDD added registry and gateway abuse tests before implementation.
+- 2026-07-12: Implemented `AgentRuntimeProviderRegistry` and gateway `RuntimeProviderService`; registered both in `AgentModule` and documented the internal boundary.
+- 2026-07-12: Independent review found two audit correctness issues. Remediated completion-audit failure handling and provider execution failures: pre-invocation denials are audited as `denied`; post-invocation errors as `failed`; completion audit failure does not misreport a completed effect as retryable.
+- 2026-07-12: Final independent security review: no findings. Final code review had one false positive: `@mosaicstack/types` is already declared in `packages/agent/package.json`.
+
+## Tests
+
+- TDD red: `pnpm --filter @mosaicstack/gateway test -- runtime-provider-registry.service.test.ts` failed before both audit remediations, as expected.
+- Focused: package registry 2 tests and gateway security boundary 7 tests pass.
+- Cold-cache: removed this worktree's `node_modules`, then `pnpm install --offline --frozen-lockfile --store-dir /home/jarvis/.local/share/pnpm/store` passed.
+- Cold-cache baseline: `TURBO_FORCE=true pnpm typecheck` — 42/42 tasks passed; `TURBO_FORCE=true pnpm lint` — 23/23 tasks passed; `TURBO_FORCE=true pnpm format:check` passed; `TURBO_FORCE=true pnpm test` — 42/42 tasks passed (gateway 548 tests passed, 11 intentionally skipped).
+
+## Risks / Blockers
+
+- The canonical durable approval implementation is currently command-specific. This card introduces a fail-closed runtime approval verifier boundary so a runtime provider cannot terminate until its exact-action verifier is wired; later provider implementations cannot bypass it.
diff --git a/docs/tess/ARCHITECTURE.md b/docs/tess/ARCHITECTURE.md
index 180cf0a..36472c4 100644
--- a/docs/tess/ARCHITECTURE.md
+++ b/docs/tess/ARCHITECTURE.md
@@ -37,6 +37,12 @@ Required operations:
 
 Every call receives an immutable, server-derived actor/tenant/channel scope and correlation ID. Caller-supplied actor IDs are forbidden. Unsupported capabilities fail closed with typed errors.
 
+### M1 Registry Boundary
+
+`@mosaicstack/agent` owns the explicit `AgentRuntimeProviderRegistry`; duplicate provider IDs are rejected rather than replaced. Gateway owns `RuntimeProviderService`, which creates a frozen `RuntimeScope` from authenticated `ActorTenantScope` and trusted ingress channel/correlation metadata before every provider call. The service checks the declared provider capability before invoking a side effect and records metadata-only audit events (`providerId`, operation, outcome, actor/tenant/channel, correlation, and resource ID). It never records message bodies, idempotency keys, or approval references.
+
+Termination is fail-closed: a runtime approval verifier must consume a one-time, exact action binding for the provider, session, actor, tenant, channel, and correlation ID before `terminate` reaches a provider. Until the durable verifier is wired, the default verifier denies termination. This internal service introduces no HTTP endpoint; later Discord, CLI, MCP, and provider adapters consume the same gateway boundary.
+
 ## Authority Model
 
 | Intent                                                                      | Owner                   | Tess behavior                                                          |
diff --git a/packages/agent/src/index.ts b/packages/agent/src/index.ts
index 0c18d5d..409ae61 100644
--- a/packages/agent/src/index.ts
+++ b/packages/agent/src/index.ts
@@ -1 +1,3 @@
 export const VERSION = '0.0.0';
+
+export * from './runtime-provider-registry.js';
diff --git a/packages/agent/src/runtime-provider-registry.test.ts b/packages/agent/src/runtime-provider-registry.test.ts
new file mode 100644
index 0000000..4e88f08
--- /dev/null
+++ b/packages/agent/src/runtime-provider-registry.test.ts
@@ -0,0 +1,95 @@
+import { describe, expect, it } from 'vitest';
+import type {
+  AgentRuntimeProvider,
+  RuntimeAttachHandle,
+  RuntimeAttachMode,
+  RuntimeCapabilitySet,
+  RuntimeHealth,
+  RuntimeMessage,
+  RuntimeScope,
+  RuntimeSession,
+  RuntimeSessionTree,
+  RuntimeStreamEvent,
+} from '@mosaicstack/types';
+import { AgentRuntimeProviderRegistry } from './runtime-provider-registry.js';
+
+class TestRuntimeProvider implements AgentRuntimeProvider {
+  readonly id = 'test-runtime';
+
+  async capabilities(_scope: RuntimeScope): Promise<RuntimeCapabilitySet> {
+    return { supported: ['session.list'] };
+  }
+
+  async health(_scope: RuntimeScope): Promise<RuntimeHealth> {
+    return { status: 'healthy', checkedAt: '2026-07-12T00:00:00.000Z' };
+  }
+
+  async listSessions(_scope: RuntimeScope): Promise<RuntimeSession[]> {
+    return [];
+  }
+
+  async getSessionTree(_scope: RuntimeScope): Promise<RuntimeSessionTree[]> {
+    return [];
+  }
+
+  async *streamSession(
+    _sessionId: string,
+    _cursor: string | undefined,
+    _scope: RuntimeScope,
+  ): AsyncIterable<RuntimeStreamEvent> {
+    return;
+  }
+
+  async sendMessage(
+    _sessionId: string,
+    _message: RuntimeMessage,
+    _scope: RuntimeScope,
+  ): Promise<void> {}
+
+  async attach(
+    _sessionId: string,
+    _mode: RuntimeAttachMode,
+    _scope: RuntimeScope,
+  ): Promise<RuntimeAttachHandle> {
+    return {
+      attachmentId: 'attachment-1',
+      sessionId: 'session-1',
+      mode: 'read',
+      expiresAt: '2026-07-12T00:00:00.000Z',
+    };
+  }
+
+  async detach(_attachmentId: string, _scope: RuntimeScope): Promise<void> {}
+
+  async terminate(_sessionId: string, _approvalRef: string, _scope: RuntimeScope): Promise<void> {}
+}
+
+describe('AgentRuntimeProviderRegistry', (): void => {
+  it('resolves only registered runtime providers', (): void => {
+    const registry = new AgentRuntimeProviderRegistry();
+    const provider = new TestRuntimeProvider();
+
+    registry.register(provider);
+
+    expect(registry.get(provider.id)).toBe(provider);
+    expect(registry.get('unknown-runtime')).toBeUndefined();
+    expect(registry.list()).toEqual([provider]);
+  });
+
+  it('rejects duplicate and blank provider identities rather than silently replacing a runtime', (): void => {
+    const registry = new AgentRuntimeProviderRegistry();
+    const provider = new TestRuntimeProvider();
+
+    registry.register(provider);
+
+    expect((): void => {
+      registry.register(provider);
+    }).toThrow(/already registered/);
+    expect((): void => {
+      registry.require('');
+    }).toThrow(/provider ID is required/);
+    expect((): void => {
+      registry.require('unknown-runtime');
+    }).toThrow(/not registered/);
+  });
+});
diff --git a/packages/agent/src/runtime-provider-registry.ts b/packages/agent/src/runtime-provider-registry.ts
new file mode 100644
index 0000000..16cb7d9
--- /dev/null
+++ b/packages/agent/src/runtime-provider-registry.ts
@@ -0,0 +1,40 @@
+import type { AgentRuntimeProvider } from '@mosaicstack/types';
+
+/**
+ * Registry for runtime providers. Registration is explicit and replacement is
+ * forbidden so a provider identity cannot be silently hijacked at runtime.
+ */
+export class AgentRuntimeProviderRegistry {
+  private readonly providers = new Map<string, AgentRuntimeProvider>();
+
+  register(provider: AgentRuntimeProvider): void {
+    const providerId = provider.id.trim();
+    if (providerId.length === 0) {
+      throw new Error('Runtime provider ID is required');
+    }
+    if (this.providers.has(providerId)) {
+      throw new Error(`Runtime provider is already registered: ${providerId}`);
+    }
+    this.providers.set(providerId, provider);
+  }
+
+  get(providerId: string): AgentRuntimeProvider | undefined {
+    return this.providers.get(providerId);
+  }
+
+  require(providerId: string): AgentRuntimeProvider {
+    const normalizedProviderId = providerId.trim();
+    if (normalizedProviderId.length === 0) {
+      throw new Error('Runtime provider ID is required');
+    }
+    const provider = this.providers.get(normalizedProviderId);
+    if (!provider) {
+      throw new Error(`Runtime provider is not registered: ${normalizedProviderId}`);
+    }
+    return provider;
+  }
+
+  list(): AgentRuntimeProvider[] {
+    return Array.from(this.providers.values());
+  }
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bf89e42..5124acd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -75,6 +75,9 @@ importers:
       '@modelcontextprotocol/sdk':
         specifier: ^1.27.1
         version: 1.27.1(zod@4.3.6)
+      '@mosaicstack/agent':
+        specifier: workspace:^
+        version: link:../../packages/agent
       '@mosaicstack/auth':
         specifier: workspace:^
         version: link:../../packages/auth