fix(extensions): restore activation rollback context

packages/coding-agent/src/sdk.ts

@@ -2576,6 +2576,11 @@ async function createAgentSessionScoped(options: CreateAgentSessionOptions): Pro
 			autoApprove: options.autoApprove ?? false,
 		});
 		const toolContextStore = new ToolContextStore(getSessionContext);
+		const setSessionActiveToolNames = (names: Iterable<string>): void => {
+			const snapshot = Array.from(names);
+			setActiveToolNames(snapshot);
+			toolContextStore.setToolNames(snapshot);
+		};
 		// Native built-in implementations backing same-tool `ctx.invokeTool`, so a tool that
 		// re-registers a built-in (e.g. wrapping `write`) can delegate to the original — reaching the
 		// unwrapped native execute, which inherits the caller's already-granted approval rather than
@@ -2789,7 +2794,6 @@ async function createAgentSessionScoped(options: CreateAgentSessionOptions): Pro
 			toolNames: string[],
 			tools: Map<string, AgentTool>,
 		): Promise<BuildSystemPromptResult> => {
-			toolContextStore.setToolNames(toolNames);
 			const promptCwd = sessionManager.getCwd();
 			const activeRepoContext = hasSession
 				? await logger.time("resolveActiveRepoContext", resolveRepoContext, promptCwd)
@@ -3042,7 +3046,7 @@ async function createAgentSessionScoped(options: CreateAgentSessionOptions): Pro
 			if (mountedNames.length > 0 && !initialToolNames.includes("write")) initialToolNames.push("write");
 		}
 
-		setActiveToolNames(initialToolNames);
+		setSessionActiveToolNames(initialToolNames);
 		const { systemPrompt } = await logger.time(
 			"buildSystemPrompt",
 			rebuildSystemPrompt,
@@ -3395,7 +3399,7 @@ async function createAgentSessionScoped(options: CreateAgentSessionOptions): Pro
 			getXdevToolEntries: () => (toolSession.xdev ? xdevEntries(toolSession.xdev) : []),
 			xdev: toolSession.xdev,
 			presentationPinnedToolNames: explicitlyRequestedToolNameSet,
-			setActiveToolNames,
+			setActiveToolNames: setSessionActiveToolNames,
 			ensureWriteRegistered,
 			getMcpServerInstructions: mcpManager
 				? () => {

packages/coding-agent/src/session/session-tools.ts

@@ -1191,12 +1191,14 @@ export class SessionTools {
 			const reconciled = await this.reconcileInspectImageTool();
 			const after = this.getEnabledToolNames().includes("inspect_image");
 			if (!reconciled || before === after) return;
+			const model = this.#host.model();
+			const modelName = model ? formatModelString(model) : "the current model";
 			this.#host.emitNotice(
 				"info",
 				after
-					? "inspect_image is now active for the selected model."
-					: "inspect_image is unavailable for the selected model.",
-				"inspect_image",
+					? `inspect_image is now available: ${modelName} has no native image input.`
+					: `inspect_image is now hidden: ${modelName} supports image input natively. Override with /vision on.`,
+				"vision",
 			);
 		});
 	}

packages/coding-agent/test/nonvision-model-switch.test.ts

@@ -40,6 +40,10 @@ describe("model switch from vision to text-only", () => {
 				rules: [],
 				contextFiles: [],
 			});
+			const notices: string[] = [];
+			const unsubscribe = session.subscribe(event => {
+				if (event.type === "notice") notices.push(`${event.source}:${event.message}`);
+			});
 			try {
 				await session.prompt("see image", { images: [{ type: "image", data: "aaaa", mimeType: "image/png" }] });
 				await session.setModel(text);
@@ -49,7 +53,12 @@ describe("model switch from vision to text-only", () => {
 				expect(
 					messages.flatMap<unknown>(message => (Array.isArray(message.content) ? message.content : [])),
 				).not.toContainEqual(expect.objectContaining({ type: "image" }));
+
+				await session.setModel(vision);
+				expect(notices.at(-1)).toContain("vision:inspect_image is now hidden:");
+				expect(notices.at(-1)).toContain("supports image input natively. Override with /vision on.");
 			} finally {
+				unsubscribe();
 				await session.dispose();
 			}
 		} finally {

packages/coding-agent/test/sdk-tool-activation.test.ts

@@ -1083,6 +1083,17 @@ describe("createAgentSession defaultInactive tool activation", () => {
 
 		const { session } = await createAgentSession({
 			...baseOptions(tempDir),
+			settings: Settings.isolated({
+				"bashInterceptor.enabled": true,
+				"bashInterceptor.patterns": [
+					{
+						pattern: "^\\s*printf\\s+",
+						tool: "detached_registration_tool",
+						message: "Use the detached registration tool.",
+					},
+				],
+			}),
+			autoApprove: true,
 			extensions: [detachedRegistrationExtension],
 			systemPrompt: defaultPrompt => {
 				if (rejectDetachedPrompt) throw new Error("expected detached registration failure");
@@ -1107,6 +1118,33 @@ describe("createAgentSession defaultInactive tool activation", () => {
 				error: "expected detached registration failure",
 			});
 			expect(session.getToolByName("detached_registration_tool")).toBeUndefined();
+			rejectDetachedPrompt = false;
+			const toolCallId = "detached-rollback-bash";
+			const mock = createMockModel({
+				responses: [
+					{
+						content: [
+							{
+								type: "toolCall",
+								id: toolCallId,
+								name: "bash",
+								arguments: { command: "printf rollback-ok" },
+							},
+						],
+					},
+					{ content: [{ type: "text", text: "done" }] },
+				],
+			});
+			vi.spyOn(session.agent, "streamFn").mockImplementation(mock.stream);
+			await withProviderAuth(["openai"], async () => {
+				await session.prompt("verify rollback context");
+				const bashResult = session.messages.find(
+					(message): message is ToolResultMessage =>
+						message.role === "toolResult" && message.toolCallId === toolCallId,
+				);
+				expect(bashResult?.isError).toBe(false);
+				expect(JSON.stringify(bashResult?.content)).toContain("rollback-ok");
+			});
 		} finally {
 			releaseDetachedRegistration.resolve();
 			await session.dispose();