diff --git a/core/config/load.ts b/core/config/load.ts
index 4a88fbcce30..e4c7e13c4f0 100644
--- a/core/config/load.ts
+++ b/core/config/load.ts
@@ -651,6 +651,7 @@ function llmToSerializedModelDescription(llm: ILLM): ModelDescription {
     envSecretLocations: llm.envSecretLocations,
     sourceFile: llm.sourceFile,
     isFromAutoDetect: llm.isFromAutoDetect,
+    toolOverrides: llm.toolOverrides,
   };
 }
 
diff --git a/core/index.d.ts b/core/index.d.ts
index 1e7c6ac4baf..ccdfcedaf07 100644
--- a/core/index.d.ts
+++ b/core/index.d.ts
@@ -1254,6 +1254,9 @@ export interface ModelDescription {
 
   sourceFile?: string;
   isFromAutoDetect?: boolean;
+
+  /** Tool overrides for this model */
+  toolOverrides?: ToolOverride[];
 }
 
 export interface JSONEmbedOptions {
diff --git a/core/tools/systemMessageTools/toolCodeblocks/index.ts b/core/tools/systemMessageTools/toolCodeblocks/index.ts
index 97baa19fa06..a2cdc393d66 100644
--- a/core/tools/systemMessageTools/toolCodeblocks/index.ts
+++ b/core/tools/systemMessageTools/toolCodeblocks/index.ts
@@ -65,13 +65,20 @@ export class SystemMessageToolCodeblocksFramework
     return toolDefinition.trim();
   }
 
-  systemMessagePrefix = `You have access to several "tools" that you can use at any time to retrieve information and/or perform tasks for the User.
-To use a tool, respond with a tool code block (\`\`\`tool) using the syntax shown in the examples below:`;
-
-  systemMessageSuffix = `If it seems like the User's request could be solved with one of the tools, choose the BEST one for the job based on the user's request and the tool descriptions
-Then send the \`\`\`tool codeblock (YOU call the tool, not the user). Always start the codeblock on a new line.
-Do not perform actions with/for hypothetical files. Ask the user or use tools to deduce which files are relevant.
-You can only call ONE tool at at time. The tool codeblock should be the last thing you say; stop your response after the tool codeblock.`;
+  systemMessagePrefix = `You have access to tools. To call a tool, you MUST respond with EXACTLY this format — a tool code block (\`\`\`tool) using the syntax shown below.
+
+CRITICAL: Follow the exact syntax. Do not use XML tags, JSON objects, or any other format for tool calls.`;
+
+  systemMessageSuffix = `RULES FOR TOOL USE:
+1. To call a tool, output a \`\`\`tool code block using EXACTLY the format shown above.
+2. Always start the code block on a new line.
+3. You can only call ONE tool at a time.
+4. The \`\`\`tool code block MUST be the last thing in your response. Stop immediately after the closing \`\`\`.
+5. Do NOT wrap tool calls in XML tags like <tool_call> or <function=...>.
+6. Do NOT use JSON format for tool calls.
+7. Do NOT invent tools that are not listed above.
+8. If the user's request can be addressed with a listed tool, use it rather than guessing.
+9. Do not perform actions with hypothetical files. Use tools to find relevant files.`;
 
   exampleDynamicToolDefinition = `
 \`\`\`tool_definition
diff --git a/gui/src/redux/thunks/streamNormalInput.ts b/gui/src/redux/thunks/streamNormalInput.ts
index 13cc5ebbf60..559bcadf96e 100644
--- a/gui/src/redux/thunks/streamNormalInput.ts
+++ b/gui/src/redux/thunks/streamNormalInput.ts
@@ -22,6 +22,7 @@ import { ThunkApiType } from "../store";
 import { constructMessages } from "../util/constructMessages";
 
 import { modelSupportsNativeTools } from "core/llm/toolSupport";
+import { applyToolOverrides } from "core/tools/applyToolOverrides";
 import { addSystemMessageToolsToSystemMessage } from "core/tools/systemMessageTools/buildToolsSystemMessage";
 import { interceptSystemToolCalls } from "core/tools/systemMessageTools/interceptSystemToolCalls";
 import { SystemMessageToolCodeblocksFramework } from "core/tools/systemMessageTools/toolCodeblocks";
@@ -93,8 +94,20 @@ export const streamNormalInput = createAsyncThunk<
       throw new Error("No chat model selected");
     }
 
-    // Get tools and filter them based on the selected model
-    const activeTools = selectActiveTools(state);
+    // Get tools and apply model-level overrides (disabled, description, etc.)
+    let activeTools = selectActiveTools(state);
+    if (selectedChatModel.toolOverrides?.length) {
+      const { tools: overriddenTools, errors } = applyToolOverrides(
+        activeTools,
+        selectedChatModel.toolOverrides,
+      );
+      activeTools = overriddenTools;
+      for (const error of errors) {
+        if (!error.fatal) {
+          console.warn(`Tool override warning: ${error.message}`);
+        }
+      }
+    }
 
     // Use the centralized selector to determine if system message tools should be used
     const useNativeTools = state.config.config.experimental