feat(core): exempt high-signal tools from output masking (#18545)

packages/core/src/services/toolOutputMaskingService.ts

@@ -12,7 +12,14 @@ import { debugLogger } from '../utils/debugLogger.js';
 import { sanitizeFilenamePart } from '../utils/fileUtils.js';
 import type { Config } from '../config/config.js';
 import { logToolOutputMasking } from '../telemetry/loggers.js';
-import { SHELL_TOOL_NAME } from '../tools/tool-names.js';
+import {
+  SHELL_TOOL_NAME,
+  ACTIVATE_SKILL_TOOL_NAME,
+  MEMORY_TOOL_NAME,
+  ASK_USER_TOOL_NAME,
+  ENTER_PLAN_MODE_TOOL_NAME,
+  EXIT_PLAN_MODE_TOOL_NAME,
+} from '../tools/tool-names.js';
 import { ToolOutputMaskingEvent } from '../telemetry/types.js';
 
 // Tool output masking defaults
@@ -23,6 +30,18 @@ export const MASKING_INDICATOR_TAG = 'tool_output_masked';
 
 export const TOOL_OUTPUTS_DIR = 'tool-outputs';
 
+/**
+ * Tools whose outputs are always high-signal and should never be masked,
+ * regardless of their position in the conversation history.
+ */
+const EXEMPT_TOOLS = new Set([
+  ACTIVATE_SKILL_TOOL_NAME,
+  MEMORY_TOOL_NAME,
+  ASK_USER_TOOL_NAME,
+  ENTER_PLAN_MODE_TOOL_NAME,
+  EXIT_PLAN_MODE_TOOL_NAME,
+]);
+
 export interface MaskingResult {
   newHistory: Content[];
   maskedCount: number;
@@ -89,6 +108,11 @@ export class ToolOutputMaskingService {
         // core intent and logic, which are harder for the model to recover if lost.
         if (!part.functionResponse) continue;
 
+        const toolName = part.functionResponse.name;
+        if (toolName && EXEMPT_TOOLS.has(toolName)) {
+          continue;
+        }
+
         const toolOutputContent = this.getToolOutputContent(part);
         if (!toolOutputContent || this.isAlreadyMasked(toolOutputContent)) {
           continue;