fix(server): Claude and every other provider get T3's browser guidance

apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.test.ts

@@ -686,6 +686,7 @@ const makeInstructionCompactionHarness = Effect.fnUntraced(function* (
     endpoint: "http://127.0.0.1:43123/mcp",
     authorizationHeader: "Bearer instruction-compaction-token",
     browserToolsAvailable: true,
+    capabilities: new Set(["preview"]),
   });
   const adapter = yield* makeAcpAdapterV2({
     instanceId,
@@ -2247,7 +2248,7 @@ describe("AcpAdapterV2", () => {
         const firstDefault = yield* runTurn(2, defaultPolicy, "First default request.");
         assert.equal(firstDefault.textBlockCount, 2);
         assert.include(firstDefault.prompt, "T3 Code interaction mode: Default");
-        assert.include(firstDefault.prompt, "## T3 Code browser");
+        assert.notInclude(firstDefault.prompt, "## T3 Code browser");
         assert.include(firstDefault.prompt, "T3 Code orchestration");
         assert.notInclude(
           firstDefault.methods,

apps/server/src/orchestration-v2/Adapters/AcpRegistryAdapterV2.test.ts

@@ -1343,7 +1343,12 @@ describe("AcpRegistryAdapterV2", () => {
               ordinal === 1
                 ? t3AcpPromptWithInstructions({
                     prompt: "test prompt",
-                    state: { interactionMode: "default", hasT3Mcp: false, hasDeviceTools: false },
+                    state: {
+                      interactionMode: "default",
+                      hasT3Mcp: false,
+                      hasDeviceTools: false,
+                      hasBrowserTools: false,
+                    },
                   })
                 : "test prompt",
           },

apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts

@@ -85,7 +85,10 @@ import { attachmentRelativePath } from "../../attachmentStore.ts";
 import { WorkflowAgentTranscriptReadObserver } from "../workflowAgentTranscript.ts";
 import * as ServerConfig from "../../config.ts";
 import * as McpProviderSession from "@t3tools/provider-core/server/mcpSession";
-import { T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH } from "@t3tools/provider-core/server/orchestrationInstructions";
+import {
+  T3_CODE_BROWSER_TOOL_INSTRUCTIONS,
+  T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH,
+} from "@t3tools/provider-core/server/orchestrationInstructions";
 import * as McpProviderSessions from "@t3tools/provider-core/server/McpProviderSessions";
 import { PreviewControlsToolkit } from "../../mcp/toolkits/previewControls/tools.ts";
 import { HtmlToolkit } from "../../mcp/toolkits/html/tools.ts";
@@ -692,7 +695,11 @@ describe("ClaudeAdapterV2 native protocol logging", () => {
 });
 
 describe("ClaudeAdapterV2 device instructions", () => {
-  const options = (input: { readonly mcp: boolean; readonly deviceToolsAvailable: boolean }) =>
+  const options = (input: {
+    readonly mcp: boolean;
+    readonly deviceToolsAvailable: boolean;
+    readonly browserToolsAvailable?: boolean;
+  }) =>
     ClaudeAdapterV2.makeClaudeQueryOptions({
       modelSelection: {
         instanceId: ProviderInstanceId.make("claudeAgent"),
@@ -705,10 +712,14 @@ describe("ClaudeAdapterV2 device instructions", () => {
         ? { mcpServers: { "t3-code": { type: "http" as const, url: "http://127.0.0.1/mcp" } } }
         : {}),
       deviceToolsAvailable: input.deviceToolsAvailable,
+      browserToolsAvailable: input.browserToolsAvailable ?? false,
       environment: {},
     });
-  const append = (input: { readonly mcp: boolean; readonly deviceToolsAvailable: boolean }) =>
-    (options(input).systemPrompt as { readonly append?: string }).append ?? "";
+  const append = (input: {
+    readonly mcp: boolean;
+    readonly deviceToolsAvailable: boolean;
+    readonly browserToolsAvailable?: boolean;
+  }) => (options(input).systemPrompt as { readonly append?: string }).append ?? "";
 
   it("gives a session with device access the device block and the ToolSearch line to load it", () => {
     const text = append({ mcp: true, deviceToolsAvailable: true });
@@ -721,10 +732,24 @@ describe("ClaudeAdapterV2 device instructions", () => {
     assert.notInclude(append({ mcp: false, deviceToolsAvailable: true }), "## T3 Code devices");
   });
 
-  it("gives native subagents the device block only in a session with device access", async () => {
+  it("gives the browser block only to a session with browser access", () => {
+    const text = append({ mcp: true, deviceToolsAvailable: false, browserToolsAvailable: true });
+    assert.include(text, T3_CODE_BROWSER_TOOL_INSTRUCTIONS.trim());
+    assert.notInclude(
+      append({ mcp: true, deviceToolsAvailable: false, browserToolsAvailable: false }),
+      "## T3 Code browser",
+    );
+    assert.notInclude(
+      append({ mcp: false, deviceToolsAvailable: false, browserToolsAvailable: true }),
+      "## T3 Code browser",
+    );
+  });
+
+  it("gives native subagents browser and device blocks only with the corresponding access", async () => {
     // Subagents start from their task prompt, not the parent's system prompt.
     const subagentContext = (input: {
       readonly mcp: boolean;
+      readonly browserToolsAvailable?: boolean;
       readonly deviceToolsAvailable: boolean;
     }) =>
       Promise.all(
@@ -753,7 +778,33 @@ describe("ClaudeAdapterV2 device instructions", () => {
         },
       },
     ]);
+    for (const deviceToolsAvailable of [false, true]) {
+      const result = await subagentContext({
+        mcp: true,
+        deviceToolsAvailable,
+        browserToolsAvailable: true,
+      });
+      assert.deepEqual(result, [
+        {
+          hookSpecificOutput: {
+            hookEventName: "SubagentStart",
+            additionalContext: [
+              T3_CODE_BROWSER_TOOL_INSTRUCTIONS.trim(),
+              ...(deviceToolsAvailable ? [T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH] : []),
+            ].join("\n\n"),
+          },
+        },
+      ]);
+    }
     assert.deepEqual(await subagentContext({ mcp: true, deviceToolsAvailable: false }), []);
+    assert.deepEqual(
+      await subagentContext({
+        mcp: false,
+        deviceToolsAvailable: true,
+        browserToolsAvailable: true,
+      }),
+      [],
+    );
     assert.deepEqual(await subagentContext({ mcp: false, deviceToolsAvailable: true }), []);
   });
 });

apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts

@@ -203,6 +203,7 @@ import {
 } from "../../provider/claudeUsageLimits.ts";
 import type { ManagedServerProvider } from "@t3tools/provider-core/server/snapshot";
 import {
+  T3_CODE_BROWSER_TOOL_INSTRUCTIONS,
   T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH,
   T3_CODE_ORCHESTRATION_INSTRUCTIONS,
 } from "@t3tools/provider-core/server/orchestrationInstructions";
@@ -1742,13 +1743,15 @@ To wait for a background command or Monitor you started (tests, a build), call \
 `;
 
 // Native subagents start from their task, not this session's system prompt.
-const subagentDeviceInstructions: HookCallback = () =>
-  Promise.resolve({
-    hookSpecificOutput: {
-      hookEventName: "SubagentStart",
-      additionalContext: T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH,
-    },
-  });
+const subagentInstructions =
+  (additionalContext: string): HookCallback =>
+  () =>
+    Promise.resolve({
+      hookSpecificOutput: {
+        hookEventName: "SubagentStart",
+        additionalContext,
+      },
+    });
 
 export function makeClaudeQueryOptions(input: {
   readonly modelSelection: ModelSelection;
@@ -1764,6 +1767,8 @@ export function makeClaudeQueryOptions(input: {
   readonly sdkSettings?: string | ClaudeSdkSettings;
   readonly environment?: NodeJS.ProcessEnv;
   readonly mcpServers?: ClaudeQueryOptions["mcpServers"];
+  /** The thread's T3 MCP session holds the `preview` capability. */
+  readonly browserToolsAvailable?: boolean;
   /** The thread's T3 MCP session holds the `device` capability. */
   readonly deviceToolsAvailable?: boolean;
   readonly tools?: ClaudeAgentSdkQueryTools;
@@ -1833,6 +1838,8 @@ export function makeClaudeQueryOptions(input: {
           ...compactQuerySettings,
           env: { ...compactQuerySettings?.env, ENABLE_TOOL_SEARCH: input.toolSearchOverride },
         } as ClaudeSdkSettings);
+  const browserInstructions =
+    input.mcpServers !== undefined && input.browserToolsAvailable === true;
   const deviceInstructions = input.mcpServers !== undefined && input.deviceToolsAvailable === true;
   const options: ClaudeAgentSdkQueryOptions = {
     model: compiledSelection.apiModelId,
@@ -1892,14 +1899,32 @@ export function makeClaudeQueryOptions(input: {
             ? ""
             : T3_CODE_ORCHESTRATION_INSTRUCTIONS +
               CLAUDE_BACKGROUND_WAIT_INSTRUCTIONS +
+              (browserInstructions ? `\n${T3_CODE_BROWSER_TOOL_INSTRUCTIONS.trim()}\n` : "") +
               (deviceInstructions
                 ? `\n${T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH}\n`
                 : "")),
         ...launchAppendSystemPrompt,
       ].join("\n\n"),
     },
-    ...(deviceInstructions
-      ? { hooks: { SubagentStart: [{ hooks: [subagentDeviceInstructions] }] } }
+    ...(deviceInstructions || browserInstructions
+      ? {
+          hooks: {
+            SubagentStart: [
+              {
+                hooks: [
+                  subagentInstructions(
+                    [
+                      ...(browserInstructions ? [T3_CODE_BROWSER_TOOL_INSTRUCTIONS.trim()] : []),
+                      ...(deviceInstructions
+                        ? [T3_CODE_DEVICE_TOOL_INSTRUCTIONS_WITH_TOOL_SEARCH]
+                        : []),
+                    ].join("\n\n"),
+                  ),
+                ],
+              },
+            ],
+          },
+        }
       : {}),
     ...(Object.keys(extraArgs).length === 0 ? {} : { extraArgs }),
   };
@@ -11015,6 +11040,7 @@ export const makeClaudeAdapterV2 = Effect.fn("makeClaudeAdapterV2")(function* (
             ...(mcpOverrides.mcpServers === undefined
               ? {}
               : { mcpServers: mcpOverrides.mcpServers }),
+            browserToolsAvailable: mcpSession?.capabilities?.has("preview") === true,
             deviceToolsAvailable: mcpSession?.capabilities?.has("device") === true,
             permissionMode: queryPolicy.permissionMode,
             ...(queryPolicy.allowDangerouslySkipPermissions === undefined