diff --git a/README.md b/README.md
index b4b2500..fde7875 100644
--- a/README.md
+++ b/README.md
@@ -1190,7 +1190,7 @@ Methods:
 - `system.capabilities` returns gateway protocol and node policy snapshot.
 
 Companion runtime helper:
-- `src/companion/runtimeClient.ts` provides a typed Node/WebSocket client for companion runtimes (macOS/iOS/Android workers) with wrappers for `node.register`, `node.capabilities.get`, `node.location.set/get`, `node.status.set`, `node.push_token.set`, `system.capabilities`, and `system.nodes`.
+- `src/companion/runtimeClient.ts` provides a typed Node/WebSocket client for companion runtimes (macOS/iOS/Android workers) with wrappers for `node.register`, `node.capabilities.get`, `node.location.set/get`, `node.status.set`, `node.push_token.set`, `system.capabilities`, `system.nodes`, and canvas artifact RPCs (`canvas.put/get/list/delete/clear`).
 - `src/companion/platformClients.ts` provides platform-focused wrappers:
   - `MacOSCompanionClient` (`platform: "macos"`, APNs push registration)
   - `IOSCompanionClient` (`platform: "ios"`, APNs push registration)
diff --git a/docs/api/PROTOCOL.md b/docs/api/PROTOCOL.md
index 965a56f..355d7c0 100644
--- a/docs/api/PROTOCOL.md
+++ b/docs/api/PROTOCOL.md
@@ -1430,5 +1430,5 @@ For more implementation details, see:
 - Protocol types: `src/gateway/protocol.ts`
 - Handlers: `src/gateway/handlers/`
 - Gateway server: `src/gateway/server.ts`
-- Companion runtime client helper: `src/companion/runtimeClient.ts`
+- Companion runtime client helper: `src/companion/runtimeClient.ts` (node + system + `canvas.*` typed RPC wrappers)
 - Platform companion wrappers: `src/companion/platformClients.ts`
diff --git a/docs/plans/state.json b/docs/plans/state.json
index 2cc21d2..3d32b27 100644
--- a/docs/plans/state.json
+++ b/docs/plans/state.json
@@ -185,6 +185,23 @@
       ],
       "test_status": "pnpm test:run src/cli/onboard.test.ts src/cli/start.test.ts src/cli/index.test.ts + pnpm typecheck passing"
     },
+    "companion-runtime-client-canvas-rpc-wrappers": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Extended companion runtime APIs with typed `canvas.*` RPC wrappers (`put/get/list/delete/clear`) and surfaced them through platform companion clients, with integration coverage against live gateway handlers and updated protocol/runtime documentation references.",
+      "files_modified": [
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "src/companion/platformClients.ts",
+        "src/companion/platformClients.test.ts",
+        "src/companion/index.ts",
+        "README.md",
+        "docs/api/PROTOCOL.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/companion/runtimeClient.test.ts src/companion/platformClients.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
+    },
     "browser-tools-activation-clarity": {
       "status": "completed",
       "date": "2026-02-17",
diff --git a/src/companion/index.ts b/src/companion/index.ts
index 2a394ab..be535e1 100644
--- a/src/companion/index.ts
+++ b/src/companion/index.ts
@@ -15,6 +15,9 @@ export type {
   SetNodeStatusInput,
   SetNodeLocationInput,
   SetNodePushTokenInput,
+  PutCanvasArtifactInput,
+  GetCanvasArtifactInput,
+  DeleteCanvasArtifactInput,
   NodeRegisterResult,
   NodeCapabilitiesResult,
   NodeStatusSetResult,
@@ -27,6 +30,12 @@ export type {
   NodeLocation,
   NodeStatus,
   NodePushSummary,
+  CanvasArtifact,
+  CanvasPutResult,
+  CanvasGetResult,
+  CanvasListResult,
+  CanvasDeleteResult,
+  CanvasClearResult,
 } from './runtimeClient.js';
 export type {
   PlatformClientOptions,
diff --git a/src/companion/platformClients.test.ts b/src/companion/platformClients.test.ts
index b700c57..066dd49 100644
--- a/src/companion/platformClients.test.ts
+++ b/src/companion/platformClients.test.ts
@@ -18,6 +18,11 @@ function createRuntimeMock(): {
   setNodePushToken: ReturnType<typeof vi.fn>;
   getSystemCapabilities: ReturnType<typeof vi.fn>;
   listSystemNodes: ReturnType<typeof vi.fn>;
+  putCanvasArtifact: ReturnType<typeof vi.fn>;
+  getCanvasArtifact: ReturnType<typeof vi.fn>;
+  listCanvasArtifacts: ReturnType<typeof vi.fn>;
+  deleteCanvasArtifact: ReturnType<typeof vi.fn>;
+  clearCanvasArtifacts: ReturnType<typeof vi.fn>;
 } {
   const connect = vi.fn(async () => undefined);
   const disconnect = vi.fn(() => undefined);
@@ -29,6 +34,11 @@ function createRuntimeMock(): {
   const setNodePushToken = vi.fn(async () => ({ updated: true }));
   const getSystemCapabilities = vi.fn(async () => ({ protocol: { version: 1 }, nodes: { enabled: true, locationEnabled: true, pushEnabled: true, allowedRoles: ['companion'], registered: true }, featureGates: {} }));
   const listSystemNodes = vi.fn(async () => ({ nodes: [], summary: { total: 0 } }));
+  const putCanvasArtifact = vi.fn(async () => ({ upserted: true, artifact: { id: 'a1' } }));
+  const getCanvasArtifact = vi.fn(async () => ({ artifact: { id: 'a1' } }));
+  const listCanvasArtifacts = vi.fn(async () => ({ artifacts: [{ id: 'a1' }] }));
+  const deleteCanvasArtifact = vi.fn(async () => ({ deleted: true }));
+  const clearCanvasArtifacts = vi.fn(async () => ({ cleared: 1 }));
 
   const runtime = {
     connect,
@@ -41,6 +51,11 @@ function createRuntimeMock(): {
     setNodePushToken,
     getSystemCapabilities,
     listSystemNodes,
+    putCanvasArtifact,
+    getCanvasArtifact,
+    listCanvasArtifacts,
+    deleteCanvasArtifact,
+    clearCanvasArtifacts,
   } as unknown as CompanionRuntimeClient;
 
   return {
@@ -55,6 +70,11 @@ function createRuntimeMock(): {
     setNodePushToken,
     getSystemCapabilities,
     listSystemNodes,
+    putCanvasArtifact,
+    getCanvasArtifact,
+    listCanvasArtifacts,
+    deleteCanvasArtifact,
+    clearCanvasArtifacts,
   };
 }
 
@@ -106,4 +126,29 @@ describe('platform companion clients', () => {
     expect(mock.setNodePushToken).toHaveBeenCalledWith({ provider: 'fcm', token: 'c'.repeat(64) });
     expect(mock.listSystemNodes).toHaveBeenCalledWith({ platform: 'android', role: 'companion' });
   });
+
+  it('macOS client forwards canvas methods to runtime client', async () => {
+    const mock = createRuntimeMock();
+    const client = new MacOSCompanionClient({ runtime: mock.runtime, nodeId: 'mac-node' });
+
+    await client.putCanvasArtifact({
+      sessionId: 'ws:test-canvas',
+      type: 'markdown',
+      content: { body: 'hello' },
+    });
+    await client.listCanvasArtifacts('ws:test-canvas');
+    await client.getCanvasArtifact({ sessionId: 'ws:test-canvas', artifactId: 'a1' });
+    await client.deleteCanvasArtifact({ sessionId: 'ws:test-canvas', artifactId: 'a1' });
+    await client.clearCanvasArtifacts('ws:test-canvas');
+
+    expect(mock.putCanvasArtifact).toHaveBeenCalledWith({
+      sessionId: 'ws:test-canvas',
+      type: 'markdown',
+      content: { body: 'hello' },
+    });
+    expect(mock.listCanvasArtifacts).toHaveBeenCalledWith('ws:test-canvas');
+    expect(mock.getCanvasArtifact).toHaveBeenCalledWith({ sessionId: 'ws:test-canvas', artifactId: 'a1' });
+    expect(mock.deleteCanvasArtifact).toHaveBeenCalledWith({ sessionId: 'ws:test-canvas', artifactId: 'a1' });
+    expect(mock.clearCanvasArtifacts).toHaveBeenCalledWith('ws:test-canvas');
+  });
 });
diff --git a/src/companion/platformClients.ts b/src/companion/platformClients.ts
index dd367bd..3ab8d0c 100644
--- a/src/companion/platformClients.ts
+++ b/src/companion/platformClients.ts
@@ -1,10 +1,18 @@
 import type {
+  CanvasClearResult,
+  CanvasDeleteResult,
+  CanvasGetResult,
+  CanvasListResult,
+  CanvasPutResult,
   CompanionRuntimeClient,
+  DeleteCanvasArtifactInput,
+  GetCanvasArtifactInput,
   NodeCapabilitiesResult,
   NodeLocationGetResult,
   NodeLocationSetResult,
   NodeRegisterResult,
   NodeStatusSetResult,
+  PutCanvasArtifactInput,
   NodePushTokenSetResult,
   SetNodeLocationInput,
   SystemCapabilitiesResult,
@@ -101,6 +109,26 @@ export class MacOSCompanionClient {
   listNodes(): Promise<SystemNodesResult> {
     return this.runtime.listSystemNodes({ platform: 'macos', role: this.role });
   }
+
+  putCanvasArtifact(input: PutCanvasArtifactInput): Promise<CanvasPutResult> {
+    return this.runtime.putCanvasArtifact(input);
+  }
+
+  getCanvasArtifact(input: GetCanvasArtifactInput): Promise<CanvasGetResult> {
+    return this.runtime.getCanvasArtifact(input);
+  }
+
+  listCanvasArtifacts(sessionId: string): Promise<CanvasListResult> {
+    return this.runtime.listCanvasArtifacts(sessionId);
+  }
+
+  deleteCanvasArtifact(input: DeleteCanvasArtifactInput): Promise<CanvasDeleteResult> {
+    return this.runtime.deleteCanvasArtifact(input);
+  }
+
+  clearCanvasArtifacts(sessionId: string): Promise<CanvasClearResult> {
+    return this.runtime.clearCanvasArtifacts(sessionId);
+  }
 }
 
 export class IOSCompanionClient {
@@ -174,6 +202,26 @@ export class IOSCompanionClient {
   listNodes(): Promise<SystemNodesResult> {
     return this.runtime.listSystemNodes({ platform: 'ios', role: this.role });
   }
+
+  putCanvasArtifact(input: PutCanvasArtifactInput): Promise<CanvasPutResult> {
+    return this.runtime.putCanvasArtifact(input);
+  }
+
+  getCanvasArtifact(input: GetCanvasArtifactInput): Promise<CanvasGetResult> {
+    return this.runtime.getCanvasArtifact(input);
+  }
+
+  listCanvasArtifacts(sessionId: string): Promise<CanvasListResult> {
+    return this.runtime.listCanvasArtifacts(sessionId);
+  }
+
+  deleteCanvasArtifact(input: DeleteCanvasArtifactInput): Promise<CanvasDeleteResult> {
+    return this.runtime.deleteCanvasArtifact(input);
+  }
+
+  clearCanvasArtifacts(sessionId: string): Promise<CanvasClearResult> {
+    return this.runtime.clearCanvasArtifacts(sessionId);
+  }
 }
 
 export class AndroidCompanionClient {
@@ -245,4 +293,24 @@ export class AndroidCompanionClient {
   listNodes(): Promise<SystemNodesResult> {
     return this.runtime.listSystemNodes({ platform: 'android', role: this.role });
   }
+
+  putCanvasArtifact(input: PutCanvasArtifactInput): Promise<CanvasPutResult> {
+    return this.runtime.putCanvasArtifact(input);
+  }
+
+  getCanvasArtifact(input: GetCanvasArtifactInput): Promise<CanvasGetResult> {
+    return this.runtime.getCanvasArtifact(input);
+  }
+
+  listCanvasArtifacts(sessionId: string): Promise<CanvasListResult> {
+    return this.runtime.listCanvasArtifacts(sessionId);
+  }
+
+  deleteCanvasArtifact(input: DeleteCanvasArtifactInput): Promise<CanvasDeleteResult> {
+    return this.runtime.deleteCanvasArtifact(input);
+  }
+
+  clearCanvasArtifacts(sessionId: string): Promise<CanvasClearResult> {
+    return this.runtime.clearCanvasArtifacts(sessionId);
+  }
 }
diff --git a/src/companion/runtimeClient.test.ts b/src/companion/runtimeClient.test.ts
index 91dcdaa..9fad243 100644
--- a/src/companion/runtimeClient.test.ts
+++ b/src/companion/runtimeClient.test.ts
@@ -224,4 +224,48 @@ describe('CompanionRuntimeClient', () => {
       client.disconnect();
     }
   });
+
+  it('supports canvas artifact lifecycle via typed helper methods', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const client = new CompanionRuntimeClient({
+      url: `ws://127.0.0.1:${TEST_PORT}`,
+      token: TEST_TOKEN,
+    });
+
+    await client.connect();
+
+    try {
+      const sessionId = 'ws:companion-canvas';
+      const put = await client.putCanvasArtifact({
+        sessionId,
+        artifactId: 'artifact-1',
+        type: 'markdown',
+        title: 'Companion note',
+        content: { body: '# Hello' },
+        metadata: { source: 'runtime-client-test' },
+      });
+      expect(put.upserted).toBe(true);
+      expect(put.artifact.id).toBe('artifact-1');
+      expect(put.artifact.type).toBe('markdown');
+
+      const list = await client.listCanvasArtifacts(sessionId);
+      expect(list.artifacts.length).toBeGreaterThanOrEqual(1);
+      expect(list.artifacts.some((artifact) => artifact.id === 'artifact-1')).toBe(true);
+
+      const get = await client.getCanvasArtifact({ sessionId, artifactId: 'artifact-1' });
+      expect(get.artifact.id).toBe('artifact-1');
+      expect(get.artifact.title).toBe('Companion note');
+
+      const del = await client.deleteCanvasArtifact({ sessionId, artifactId: 'artifact-1' });
+      expect(del.deleted).toBe(true);
+
+      const clear = await client.clearCanvasArtifacts(sessionId);
+      expect(clear.cleared).toBe(0);
+    } finally {
+      client.disconnect();
+    }
+  });
 });
diff --git a/src/companion/runtimeClient.ts b/src/companion/runtimeClient.ts
index 805f03e..6e0aca8 100644
--- a/src/companion/runtimeClient.ts
+++ b/src/companion/runtimeClient.ts
@@ -185,6 +185,56 @@ export interface SetNodeLocationInput extends Omit<NodeLocationSetParams, 'conne
 
 export interface SetNodePushTokenInput extends Omit<NodePushTokenSetParams, 'connectionId'> {}
 
+export interface CanvasArtifact {
+  id: string;
+  type: string;
+  title?: string;
+  content: unknown;
+  metadata?: Record<string, unknown>;
+  createdAt: number;
+  updatedAt: number;
+}
+
+export interface PutCanvasArtifactInput {
+  sessionId: string;
+  artifactId?: string;
+  type: string;
+  title?: string;
+  content: unknown;
+  metadata?: Record<string, unknown>;
+}
+
+export interface GetCanvasArtifactInput {
+  sessionId: string;
+  artifactId: string;
+}
+
+export interface DeleteCanvasArtifactInput {
+  sessionId: string;
+  artifactId: string;
+}
+
+export interface CanvasPutResult {
+  artifact: CanvasArtifact;
+  upserted: boolean;
+}
+
+export interface CanvasGetResult {
+  artifact: CanvasArtifact;
+}
+
+export interface CanvasListResult {
+  artifacts: CanvasArtifact[];
+}
+
+export interface CanvasDeleteResult {
+  deleted: boolean;
+}
+
+export interface CanvasClearResult {
+  cleared: number;
+}
+
 export class GatewayRpcError extends Error {
   readonly code: number;
 
@@ -378,6 +428,39 @@ export class CompanionRuntimeClient {
     });
   }
 
+  putCanvasArtifact(input: PutCanvasArtifactInput): Promise<CanvasPutResult> {
+    return this.call<CanvasPutResult>('canvas.put', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+      type: input.type,
+      title: input.title,
+      content: input.content,
+      metadata: input.metadata,
+    });
+  }
+
+  getCanvasArtifact(input: GetCanvasArtifactInput): Promise<CanvasGetResult> {
+    return this.call<CanvasGetResult>('canvas.get', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+    });
+  }
+
+  listCanvasArtifacts(sessionId: string): Promise<CanvasListResult> {
+    return this.call<CanvasListResult>('canvas.list', { sessionId });
+  }
+
+  deleteCanvasArtifact(input: DeleteCanvasArtifactInput): Promise<CanvasDeleteResult> {
+    return this.call<CanvasDeleteResult>('canvas.delete', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+    });
+  }
+
+  clearCanvasArtifacts(sessionId: string): Promise<CanvasClearResult> {
+    return this.call<CanvasClearResult>('canvas.clear', { sessionId });
+  }
+
   private handleMessage(raw: string): void {
     let parsed: RpcMessage;
     try {