diff --git a/studio/frontend/src/features/chat/api/chat-adapter.ts b/studio/frontend/src/features/chat/api/chat-adapter.ts
index a5a77b0863..c214c17c0a 100644
--- a/studio/frontend/src/features/chat/api/chat-adapter.ts
+++ b/studio/frontend/src/features/chat/api/chat-adapter.ts
@@ -869,6 +869,38 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
         throw new Error("Missing connection API key.");
       }
 
+      const webSearchEnabledForThisTurn =
+        Boolean(
+          externalProvider &&
+            toolsEnabled &&
+            providerSupportsBuiltinWebSearch(externalProvider.providerType),
+        );
+      const codeExecEnabledForThisTurn =
+        Boolean(
+          externalProvider &&
+            externalSelection &&
+            codeToolsEnabled &&
+            providerSupportsBuiltinCodeExecution(
+              externalProvider.providerType,
+              externalSelection.modelId,
+              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.
+      const webFetchEnabledForThisTurn =
+        Boolean(
+          externalProvider &&
+            toolsEnabled &&
+            providerSupportsBuiltinWebFetch(externalProvider.providerType),
+        );
+      const providerShipsWebFetch = Boolean(
+        externalProvider &&
+          providerSupportsBuiltinWebFetch(externalProvider.providerType),
+      );
+
       const outboundMessages = messages
         .map(toOpenAIMessage)
         .filter((message): message is NonNullable<typeof message> =>
@@ -883,6 +915,62 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
           content: safeSystemPrompt.trim(),
         });
       }
+      let disabledToolGuard: string | null = null;
+      const disabledToolGuardProviderType = externalProvider?.providerType;
+      if (
+        disabledToolGuardProviderType === "anthropic" ||
+        disabledToolGuardProviderType === "openai"
+      ) {
+        const webLabel = providerShipsWebFetch
+          ? "web search or web fetch"
+          : "web search";
+        if (!webSearchEnabledForThisTurn && !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) {
+          disabledToolGuard =
+            `You do not have ${webLabel} tools in this conversation. ` +
+            "You may still use code execution tools when they are available and useful. " +
+            "If a request genuinely requires live data fetch or web search tool use, " +
+            "inform the user that you do not have access to these capabilities. " +
+            "Do not return tool-call syntax inside your response.";
+        } else if (!codeExecEnabledForThisTurn) {
+          disabledToolGuard =
+            "You do not have code execution tools in this conversation. " +
+            `You may still use ${webLabel} tools when they are available and useful. ` +
+            "If a request genuinely requires running code or code execution tool use, " +
+            "inform the user that you do not have access to these capabilities. " +
+            "Do not return tool-call syntax inside your response.";
+        }
+      }
+      if (disabledToolGuard) {
+        const firstMessage = outboundMessages[0];
+        if (firstMessage?.role === "system") {
+          if (typeof firstMessage.content === "string") {
+            outboundMessages[0] = {
+              ...firstMessage,
+              content: `${firstMessage.content}\n\n${disabledToolGuard}`,
+            };
+          } else {
+            outboundMessages[0] = {
+              ...firstMessage,
+              content: [
+                ...firstMessage.content,
+                { type: "text", text: `\n\n${disabledToolGuard}` },
+              ],
+            };
+          }
+        } else {
+          outboundMessages.unshift({
+            role: "system",
+            content: disabledToolGuard,
+          });
+        }
+      }
       const imageBase64 = findLatestUserImageBase64(messages);
       const audioBase64 = findLatestUserAudioBase64(messages);
 
@@ -1137,13 +1225,6 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
             // (sent as `container` on /v1/messages).
             let openaiCodeExecContainerId: string | null = null;
             let anthropicCodeExecContainerId: string | null = null;
-            const codeExecEnabledForThisTurn =
-              codeToolsEnabled &&
-              providerSupportsBuiltinCodeExecution(
-                externalProvider.providerType,
-                externalSelection.modelId,
-                externalProvider.baseUrl,
-              );
             if (codeExecEnabledForThisTurn && resolvedThreadId) {
               try {
                 const thread = await getStoredChatThread(resolvedThreadId);
@@ -1313,25 +1394,13 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
               // translates enabled_tools into each provider's tool
               // schema — for Anthropic that's the entries appended to
               // body["tools"] inside _stream_anthropic.
-              ...((toolsEnabled &&
-                providerSupportsBuiltinWebSearch(
-                  externalProvider.providerType,
-                )) ||
-              (codeToolsEnabled &&
-                providerSupportsBuiltinCodeExecution(
-                  externalProvider.providerType,
-                  externalSelection.modelId,
-                  externalProvider.baseUrl,
-                ))
+              ...(webSearchEnabledForThisTurn ||
+              webFetchEnabledForThisTurn ||
+              codeExecEnabledForThisTurn
                 ? {
                     enable_tools: true,
                     enabled_tools: [
-                      ...(toolsEnabled &&
-                      providerSupportsBuiltinWebSearch(
-                        externalProvider.providerType,
-                      )
-                        ? ["web_search"]
-                        : []),
+                      ...(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
@@ -1339,20 +1408,8 @@ export function createOpenAIStreamAdapter(): ChatModelAdapter {
                       // 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.
-                      ...(toolsEnabled &&
-                      providerSupportsBuiltinWebFetch(
-                        externalProvider.providerType,
-                      )
-                        ? ["web_fetch"]
-                        : []),
-                      ...(codeToolsEnabled &&
-                      providerSupportsBuiltinCodeExecution(
-                        externalProvider.providerType,
-                        externalSelection.modelId,
-                        externalProvider.baseUrl,
-                      )
-                        ? ["code_execution"]
-                        : []),
+                      ...(webFetchEnabledForThisTurn ? ["web_fetch"] : []),
+                      ...(codeExecEnabledForThisTurn ? ["code_execution"] : []),
                     ],
                   }
                 : {}),