Studio: standalone Fetch pill for Anthropic web_fetch

studio/backend/core/inference/external_provider.py

@@ -1509,25 +1509,19 @@ async def _stream_anthropic(
             )
             body["tools"] = anthropic_tools
 
-        # Anthropic server-side web_fetch — see
-        #   https://platform.claude.com/docs/en/agents-and-tools/tool-use/web-fetch-tool
-        # `web_fetch_20250910` reads a single URL (text or PDF) and
-        # returns a document block in a `web_fetch_tool_result`. For
-        # safety Anthropic only lets the model fetch URLs that already
-        # appeared in the conversation (user message, prior tool
-        # result, web_search hit) — there is no domain restriction we
-        # have to apply locally. No beta header is required today; the
-        # tool ships under the standard `2023-06-01` API version. We
-        # mirror the web_search wiring: max_uses cap, opt in via
-        # `enabled_tools=["web_fetch"]`, citations off by default
-        # because the frontend already paints source pills from the
-        # generic tool_end payload.
+        # Anthropic server-side web_fetch reads a single URL (text/PDF)
+        # and returns a `web_fetch_tool_result` document block. Opt in
+        # via `enabled_tools=["web_fetch"]`; no beta header required.
+        # `_anthropic_web_fetch_version` picks `web_fetch_20260209`
+        # (dynamic filtering) for Opus 4.6/4.7 + Sonnet 4.6, falling
+        # back to `web_fetch_20250910` elsewhere; mismatched variants
+        # return 400 so the per-model picker is required.
         web_fetch_enabled = bool(enabled_tools and "web_fetch" in enabled_tools)
         if web_fetch_enabled:
             anthropic_tools = list(body.get("tools") or [])
             anthropic_tools.append(
                 {
-                    "type": "web_fetch_20250910",
+                    "type": _anthropic_web_fetch_version(model),
                     "name": "web_fetch",
                     "max_uses": 5,
                 }

studio/backend/tests/test_anthropic_web_fetch.py

@@ -2,26 +2,12 @@
 # Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
 
 """
-Unit tests for Anthropic's server-side `web_fetch_20250910` tool
-translation in `_stream_anthropic`.
-
-Covers:
-- Request body: when ``enabled_tools=["web_fetch"]``, the outbound
-  ``tools`` array carries ``{"type":"web_fetch_20250910",
-  "name":"web_fetch", "max_uses":5}``. No beta header is required.
-- Combined request: ``enabled_tools=["web_search","web_fetch",
-  "code_execution"]`` sends all three tool entries.
-- Disabled by default: with ``enabled_tools=["web_search"]`` (or None),
-  the body does NOT carry a web_fetch entry.
-- SSE translation (success): a `web_fetch` server_tool_use streaming
-  ``{"url": "..."}`` followed by a `web_fetch_tool_result` block with
-  a document source emits one ``tool_start`` and one ``tool_end``
-  `_toolEvent`. The ``tool_start.arguments.url`` matches the fetched
-  URL and the ``tool_end.result`` carries the Title / URL / snippet
-  prefix the source-pill renderer expects.
-- SSE translation (error): a `web_fetch_tool_error` with
-  ``error_code="url_not_accessible"`` renders as ``"Error:
-  url_not_accessible"`` in the tool_end result.
+Unit tests for Anthropic's `web_fetch_20250910` / `web_fetch_20260209`
+translation in ``_stream_anthropic``. Covers request body emission
+(version picked by ``_anthropic_web_fetch_version``: ``_20260209`` for
+Opus 4.6/4.7 + Sonnet 4.6, ``_20250910`` otherwise), combined tool
+requests, off-by-default behavior, and SSE translation of success and
+``url_not_accessible`` error paths into ``tool_start`` / ``tool_end``.
 """
 
 import asyncio
@@ -117,8 +103,9 @@ async def run():
 
     body = captured["body"]
     tools = body.get("tools") or []
+    # claude-opus-4-7 routes web_fetch to _20260209 (dynamic filtering).
     assert {
-        "type": "web_fetch_20250910",
+        "type": "web_fetch_20260209",
         "name": "web_fetch",
         "max_uses": 5,
     } in tools
@@ -157,13 +144,10 @@ async def run():
 
     tools = captured["body"].get("tools") or []
     tool_types = [t.get("type") for t in tools]
-    # After PR 5679's per-model tool version dispatch landed,
-    # claude-opus-4-7 routes web_search to the _20260209 variant and
-    # code_execution to _20260120. web_fetch still hardcodes
-    # _20250910 today; see follow-up to thread it through
-    # _anthropic_web_fetch_version.
+    # claude-opus-4-7 routes web_search and web_fetch to _20260209
+    # and code_execution to _20260120 (per PR 5679 dispatch).
     assert "web_search_20260209" in tool_types, tool_types
-    assert "web_fetch_20250910" in tool_types, tool_types
+    assert "web_fetch_20260209" in tool_types, tool_types
     assert "code_execution_20260120" in tool_types, tool_types
     # Code-execution still adds its beta flag; web_fetch must not
     # have accidentally stripped it.
@@ -199,7 +183,9 @@ async def run():
     _drive(run())
 
     tools = captured["body"].get("tools") or []
-    assert all(t.get("type") != "web_fetch_20250910" for t in tools)
+    assert all(
+        t.get("type") not in ("web_fetch_20250910", "web_fetch_20260209") for t in tools
+    )
 
 
 # ── SSE translation ─────────────────────────────────────────────────

studio/frontend/src/features/chat/api/chat-adapter.ts

@@ -833,7 +833,13 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
       // Re-read store after potential auto-load / model ready wait
       runtime = useChatRuntimeStore.getState();
       const { params } = runtime;
-      const { supportsTools, toolsEnabled, codeToolsEnabled, imageToolsEnabled } = runtime;
+      const {
+        supportsTools,
+        toolsEnabled,
+        codeToolsEnabled,
+        imageToolsEnabled,
+        webFetchToolsEnabled,
+      } = runtime;
       const externalSelection = parseExternalModelId(params.checkpoint);
       const isExternalRequest = externalSelection !== null;
       if (
@@ -889,14 +895,14 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
               externalProvider.baseUrl,
             ),
         );
-      // web_fetch shares the Search pill with web_search (no separate
-      // UI toggle), so it follows toolsEnabled. Anthropic is the only
-      // provider that ships it today; on others providerSupportsBuiltinWebFetch
-      // returns false and this stays inert.
+      // Fetch pill is independent of Search (Anthropic bills web_fetch
+      // separately from web_search). Sourced from `webFetchToolsEnabled`;
+      // on providers without web_fetch the toggle is forced off in
+      // chat-page's runtime setState.
       const webFetchEnabledForThisTurn =
         Boolean(
           externalProvider &&
-            toolsEnabled &&
+            webFetchToolsEnabled &&
             providerSupportsBuiltinWebFetch(externalProvider.providerType),
         );
       const providerShipsWebFetch = Boolean(
@@ -941,14 +947,20 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
         const webLabel = providerShipsWebFetch
           ? "web search or web fetch"
           : "web search";
-        if (!webSearchEnabledForThisTurn && !codeExecEnabledForThisTurn) {
+        // Treat search and fetch as a single "any web tool" axis so
+        // the guard only warns when neither pill is on; checking
+        // webSearchEnabledForThisTurn alone mis-fired when only Fetch
+        // was on and suppressed live web_fetch calls.
+        const anyWebEnabledForThisTurn =
+          webSearchEnabledForThisTurn || webFetchEnabledForThisTurn;
+        if (!anyWebEnabledForThisTurn && !codeExecEnabledForThisTurn) {
           disabledToolGuard =
             `You do not have ${webLabel} or code execution tools in this conversation. ` +
             "Answer from your own knowledge. " +
             "If a request genuinely requires tool use, live data fetch or running code, " +
             "inform the user that you do not have access to these capabilities. " +
             "Do not return tool-call syntax inside your response.";
-        } else if (!webSearchEnabledForThisTurn) {
+        } else if (!anyWebEnabledForThisTurn) {
           disabledToolGuard =
             `You do not have ${webLabel} tools in this conversation. ` +
             "You may still use code execution tools when they are available and useful. " +
@@ -1419,13 +1431,8 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
                     enable_tools: true,
                     enabled_tools: [
                       ...(webSearchEnabledForThisTurn ? ["web_search"] : []),
-                      // Pair web_fetch with the Search pill on any
-                      // provider that ships it (Anthropic today). The
-                      // common workflow is "search returns URLs, fetch
-                      // reads them"; without web_fetch the model can
-                      // surface a citation but cannot quote from the
-                      // page body, which is the whole point of the
-                      // tool. There is no separate UI toggle yet.
+                      // web_fetch has its own Fetch pill, independent
+                      // of Search. Anthropic-only today.
                       ...(webFetchEnabledForThisTurn ? ["web_fetch"] : []),
                       ...(codeExecEnabledForThisTurn ? ["code_execution"] : []),
                       // OpenAI Responses-API only: `image_generation`

studio/frontend/src/features/chat/chat-page.tsx

@@ -57,6 +57,7 @@ import {
   getProviderCapabilities,
   providerSupportsBuiltinCodeExecution,
   providerSupportsBuiltinImageGeneration,
+  providerSupportsBuiltinWebFetch,
   providerSupportsBuiltinWebSearch,
 } from "./provider-capabilities";
 import { ChatRuntimeProvider } from "./runtime-provider";
@@ -71,6 +72,7 @@ import {
   CHAT_CODE_TOOLS_ENABLED_KEY,
   CHAT_IMAGE_TOOLS_ENABLED_KEY,
   CHAT_TOOLS_ENABLED_KEY,
+  CHAT_WEB_FETCH_TOOLS_ENABLED_KEY,
   loadOptionalBool,
   useChatRuntimeStore,
 } from "./stores/chat-runtime-store";
@@ -779,6 +781,9 @@ export function ChatPage(): ReactElement {
         selection.modelId,
         provider?.baseUrl,
       );
+    const supportsBuiltinWebFetch = providerSupportsBuiltinWebFetch(
+      provider?.providerType,
+    );
     // Kimi's k2.6/k2.5 default to thinking enabled on the server side
     // (per https://platform.kimi.ai/docs/models). Mirror that default
     // in the UI so the Think pill comes up clicked when the user picks
@@ -801,6 +806,9 @@ export function ChatPage(): ReactElement {
     const storedImageToolsEnabled = loadOptionalBool(
       CHAT_IMAGE_TOOLS_ENABLED_KEY,
     );
+    const storedWebFetchToolsEnabled = loadOptionalBool(
+      CHAT_WEB_FETCH_TOOLS_ENABLED_KEY,
+    );
     const nextToolsEnabled = supportsBuiltinWebSearch
       ? isKimi
         ? false
@@ -834,13 +842,18 @@ export function ChatPage(): ReactElement {
       supportsBuiltinWebSearch,
       supportsBuiltinCodeExecution,
       supportsBuiltinImageGeneration,
+      supportsBuiltinWebFetch,
       toolsEnabled: nextToolsEnabled,
       codeToolsEnabled: supportsBuiltinCodeExecution
         ? (storedCodeToolsEnabled ?? false)
         : false,
       imageToolsEnabled: supportsBuiltinImageGeneration
         ? (storedImageToolsEnabled ?? false)
         : false,
+      // Default Fetch off (Anthropic bills per fetch); deliberate opt-in.
+      webFetchToolsEnabled: supportsBuiltinWebFetch
+        ? (storedWebFetchToolsEnabled ?? false)
+        : false,
     });
   }, [externalProvidersForChat, inferenceParams.checkpoint]);
   const canCompare = useMemo(() => {
@@ -1008,6 +1021,9 @@ export function ChatPage(): ReactElement {
             selectedExternal?.modelId,
             selectedProvider?.baseUrl,
           );
+        const supportsBuiltinWebFetch = providerSupportsBuiltinWebFetch(
+          selectedProvider?.providerType,
+        );
         // See sibling useEffect above: Kimi's k2.x default to thinking
         // enabled, so the Think pill comes up clicked. Search pill stays
         // off by default; mutual exclusion flips them via the composer.
@@ -1026,6 +1042,9 @@ export function ChatPage(): ReactElement {
         const storedImageToolsEnabled = loadOptionalBool(
           CHAT_IMAGE_TOOLS_ENABLED_KEY,
         );
+        const storedWebFetchToolsEnabled = loadOptionalBool(
+          CHAT_WEB_FETCH_TOOLS_ENABLED_KEY,
+        );
         const nextToolsEnabled = supportsBuiltinWebSearch
           ? isKimi
             ? false
@@ -1063,13 +1082,17 @@ export function ChatPage(): ReactElement {
           supportsBuiltinWebSearch,
           supportsBuiltinCodeExecution,
           supportsBuiltinImageGeneration,
+          supportsBuiltinWebFetch,
           toolsEnabled: nextToolsEnabled,
           codeToolsEnabled: supportsBuiltinCodeExecution
             ? (storedCodeToolsEnabled ?? false)
             : false,
           imageToolsEnabled: supportsBuiltinImageGeneration
             ? (storedImageToolsEnabled ?? false)
             : false,
+          webFetchToolsEnabled: supportsBuiltinWebFetch
+            ? (storedWebFetchToolsEnabled ?? false)
+            : false,
           ...(stillOnOpenRouterFree ? {} : { lastOpenRouterChosenModel: null }),
         });
         return;

studio/frontend/src/features/chat/provider-capabilities.ts

@@ -123,11 +123,9 @@ export function providerSupportsBuiltinWebSearch(
 
 /**
  * Whether the external provider exposes a server-side web_fetch tool
- * that retrieves a single URL (text or PDF) and emits a document block.
- * Only Anthropic ships one today (`web_fetch_20250910`); the chat
- * composer pairs it with the Search pill because the typical workflow
- * is "search returns URLs, fetch reads them" and the UI doesn't (yet)
- * expose web_fetch as an independent toggle.
+ * (single URL, text or PDF) emitting a document block. Anthropic-only
+ * today (`web_fetch_20250910` / `web_fetch_20260209`). Gates the
+ * composer's standalone Fetch pill, independent of Search.
  */
 export function providerSupportsBuiltinWebFetch(
   providerType: string | null | undefined,

studio/frontend/src/features/chat/shared-composer.tsx

@@ -21,7 +21,7 @@ import { isTauri } from "@/lib/api-base";
 import { isMultimodalResponse } from "./types/api";
 import { getImageInputUnavailableReason } from "./utils/image-input-support";
 import { useAui } from "@assistant-ui/react";
-import { ArrowUpIcon, GlobeIcon, HeadphonesIcon, ImageIcon, LightbulbIcon, LightbulbOffIcon, MicIcon, PlusIcon, SquareIcon, XIcon } from "lucide-react";
+import { ArrowUpIcon, DownloadIcon, GlobeIcon, HeadphonesIcon, ImageIcon, LightbulbIcon, LightbulbOffIcon, MicIcon, PlusIcon, SquareIcon, XIcon } from "lucide-react";
 import { toast } from "@/lib/toast";
 import { loadModel, validateModel } from "./api/chat-api";
 import { parseExternalModelId, providerTypeSupportsVision } from "./external-providers";
@@ -34,6 +34,7 @@ import {
   getExternalReasoningCapabilities,
   providerSupportsBuiltinCodeExecution,
   providerSupportsBuiltinImageGeneration,
+  providerSupportsBuiltinWebFetch,
 } from "./provider-capabilities";
 import {
   type CompositionEvent,
@@ -336,6 +337,12 @@ export function SharedComposer({
   const setImageToolsEnabled = useChatRuntimeStore(
     (s) => s.setImageToolsEnabled,
   );
+  const webFetchToolsEnabled = useChatRuntimeStore(
+    (s) => s.webFetchToolsEnabled,
+  );
+  const setWebFetchToolsEnabled = useChatRuntimeStore(
+    (s) => s.setWebFetchToolsEnabled,
+  );
   const lastOpenRouterChosenModel = useChatRuntimeStore(
     (s) => s.lastOpenRouterChosenModel,
   );
@@ -426,6 +433,9 @@ export function SharedComposer({
     effectiveExternalModelId,
     selectedExternalProvider?.baseUrl,
   );
+  const supportsBuiltinWebFetch = providerSupportsBuiltinWebFetch(
+    selectedExternalProvider?.providerType,
+  );
   const searchDisabled =
     !modelLoaded || !(supportsTools || supportsBuiltinWebSearch);
   const codeDisabled =
@@ -437,6 +447,9 @@ export function SharedComposer({
   // the pill row stays compact for providers without the capability.
   const imageDisabled = !modelLoaded || !supportsBuiltinImageGeneration;
   const showImagePill = supportsBuiltinImageGeneration;
+  // Fetch pill: Anthropic-only (web_fetch_20250910 / web_fetch_20260209).
+  const webFetchDisabled = !modelLoaded || !supportsBuiltinWebFetch;
+  const showWebFetchPill = supportsBuiltinWebFetch;
   // Backwards-compatible alias for any other call site that may still
   // reference `toolsDisabled` (rare; both pills used it before).
   const toolsDisabled = codeDisabled;
@@ -1106,6 +1119,23 @@ export function SharedComposer({
               <span>Images</span>
             </button>
           )}
+          {showWebFetchPill && (
+            <button
+              type="button"
+              disabled={webFetchDisabled}
+              onClick={() => setWebFetchToolsEnabled(!webFetchToolsEnabled)}
+              className="composer-pill-btn"
+              data-active={
+                webFetchToolsEnabled && !webFetchDisabled ? "true" : "false"
+              }
+              aria-label={
+                webFetchToolsEnabled ? "Disable URL fetch" : "Enable URL fetch"
+              }
+            >
+              <DownloadIcon className="size-3.5" />
+              <span>Fetch</span>
+            </button>
+          )}
         </div>
         <div className="flex items-center gap-1">
           {dictationSupported && (