[Agent Builder] do not store filestore tool calls in filestore

x-pack/platform/packages/shared/agent-builder/agent-builder-server/runner/tool_manager.ts

@@ -8,6 +8,7 @@
 import type { StructuredTool } from '@langchain/core/tools';
 import type { BrowserApiToolMetadata } from '@kbn/agent-builder-common';
 import type { Logger } from '@kbn/logging';
+import type { ToolReturnSummarizerFn } from '../tools/builtin';
 import type { AgentEventEmitterFn, ExecutableTool } from '..';
 
 export interface ToolManagerParams {
@@ -83,4 +84,10 @@ export interface ToolManager {
    * @returns array of internal tool IDs
    */
   getDynamicToolIds(): string[];
+
+  /**
+   * Gets the summarizer function for a tool by its internal tool ID.
+   * Returns undefined if the tool is not found or has no summarizer.
+   */
+  getSummarizer(toolId: string): ToolReturnSummarizerFn | undefined;
 }

x-pack/platform/packages/shared/agent-builder/agent-builder-server/runner/tool_provider.ts

@@ -10,6 +10,7 @@ import type { MaybePromise } from '@kbn/utility-types';
 import type { KibanaRequest } from '@kbn/core-http-server';
 import type { ToolDefinition, ToolType } from '@kbn/agent-builder-common';
 import type { RunToolReturn, ScopedRunnerRunToolsParams } from './runner';
+import type { ToolReturnSummarizerFn } from '../tools/builtin';
 
 /**
  * Common interface shared across all tool providers.
@@ -50,6 +51,12 @@ export interface ExecutableTool<
    * When provided, will replace the description when converting to llm tool.
    */
   getLlmDescription?: LlmDescriptionHandler<TConfig>;
+  /**
+   * Optional function to summarize a tool return for conversation history.
+   * When provided, this function will be called when processing conversation history
+   * to replace large tool results with compact summaries.
+   */
+  summarizeToolReturn?: ToolReturnSummarizerFn;
 }
 
 export interface LLmDescriptionHandlerParams<TConfig extends object = {}> {

x-pack/platform/packages/shared/agent-builder/agent-builder-server/tools/builtin.ts

@@ -134,6 +134,12 @@ export interface BuiltinToolDefinition<RunInput extends ZodObject<any> = ZodObje
    * This helps prevent context bloat in long conversations.
    */
   summarizeToolReturn?: ToolReturnSummarizerFn;
+  /**
+   * When true, results from this tool will not be stored in the filestore.
+   * Tools with this flag must also define {@link summarizeToolReturn} to provide
+   * a placeholder for the removed results in conversation history.
+   */
+  excludeFromFilestore?: boolean;
 }
 
 type StaticToolRegistrationMixin<T extends ToolDefinition> = Omit<T, 'readonly'> &

x-pack/platform/packages/shared/agent-builder/agent-builder-server/tools/internal.ts

@@ -52,6 +52,10 @@ export interface InternalToolDefinition<
    * Tool call policy to control tool call confirmation behavior
    */
   confirmation?: ToolConfirmationPolicy;
+  /**
+   * When true, results from this tool will not be stored in the filestore.
+   */
+  excludeFromFilestore?: boolean;
 }
 
 export type InternalToolAvailabilityHandler = (

x-pack/platform/plugins/shared/agent_builder/server/services/agents/modes/default/run_chat_agent.ts

@@ -168,6 +168,7 @@ export const runDefaultAgentMode: RunChatAgentFn = async (
   // Create unified result transformer for tool result optimization
   const resultTransformer = createResultTransformer({
     toolRegistry,
+    toolManager,
     filestore,
     filestoreEnabled: experimentalFeatures.filestore,
   });

x-pack/platform/plugins/shared/agent_builder/server/services/agents/modes/utils/create_result_transformer.test.ts

@@ -8,6 +8,7 @@
 import type { ToolCallWithResult, ToolResult } from '@kbn/agent-builder-common';
 import { ToolResultType } from '@kbn/agent-builder-common';
 import type { IFileStore, FileEntry } from '@kbn/agent-builder-server/runner/filestore';
+import type { ToolManager } from '@kbn/agent-builder-server/runner/tool_manager';
 import type { ToolRegistry } from '@kbn/agent-builder-server';
 import {
   createResultTransformer,
@@ -61,6 +62,16 @@ describe('createResultTransformer', () => {
       list: jest.fn(async () => []),
     } as unknown as ToolRegistry);
 
+  const createMockToolManager = (
+    summarizers: Map<
+      string,
+      (step: ToolCallWithResult) => ToolResult[] | null | undefined
+    > = new Map()
+  ): ToolManager =>
+    ({
+      getSummarizer: jest.fn((toolId: string) => summarizers.get(toolId)),
+    } as unknown as ToolManager);
+
   describe('tool-specific summarization', () => {
     it('applies summarizeToolReturn when tool has it defined', async () => {
       const toolWithSummarizer = {
@@ -78,6 +89,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -106,6 +118,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -130,6 +143,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -150,6 +164,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -163,6 +178,82 @@ describe('createResultTransformer', () => {
       expect(result).toHaveLength(1);
       expect(result[0].data).toEqual({ original: 'data' });
     });
+
+    it('prefers toolManager summarizer over toolRegistry', async () => {
+      const managerSummarizer = jest.fn((step: ToolCallWithResult) => [
+        {
+          tool_result_id: 'manager-summarized',
+          type: ToolResultType.other,
+          data: { summary: 'From manager' },
+        },
+      ]);
+
+      const registrySummarizer = {
+        summarizeToolReturn: jest.fn((step: ToolCallWithResult) => [
+          {
+            tool_result_id: 'registry-summarized',
+            type: ToolResultType.other,
+            data: { summary: 'From registry' },
+          },
+        ]),
+      };
+
+      const toolManager = createMockToolManager(new Map([['search', managerSummarizer]]));
+      const toolRegistry = createMockToolRegistry(new Map([['search', registrySummarizer as any]]));
+      const filestore = createMockFileStore(new Map());
+
+      const transformer = createResultTransformer({
+        toolRegistry,
+        toolManager,
+        filestore,
+        filestoreEnabled: false,
+      });
+
+      const toolCall = makeToolCallWithResult('call-1', 'search', [
+        { tool_result_id: 'result-1', type: ToolResultType.other, data: { original: 'data' } },
+      ]);
+
+      const result = await transformer(toolCall);
+
+      expect(managerSummarizer).toHaveBeenCalledWith(toolCall);
+      expect(registrySummarizer.summarizeToolReturn).not.toHaveBeenCalled();
+      expect(result).toHaveLength(1);
+      expect(result[0].data).toEqual({ summary: 'From manager', _summary: true });
+    });
+
+    it('falls back to toolRegistry when toolManager has no summarizer', async () => {
+      const registrySummarizer = {
+        summarizeToolReturn: jest.fn((step: ToolCallWithResult) => [
+          {
+            tool_result_id: 'registry-summarized',
+            type: ToolResultType.other,
+            data: { summary: 'From registry' },
+          },
+        ]),
+      };
+
+      const toolManager = createMockToolManager(new Map());
+      const toolRegistry = createMockToolRegistry(new Map([['search', registrySummarizer as any]]));
+      const filestore = createMockFileStore(new Map());
+
+      const transformer = createResultTransformer({
+        toolRegistry,
+        toolManager,
+        filestore,
+        filestoreEnabled: false,
+      });
+
+      const toolCall = makeToolCallWithResult('call-1', 'search', [
+        { tool_result_id: 'result-1', type: ToolResultType.other, data: { original: 'data' } },
+      ]);
+
+      const result = await transformer(toolCall);
+
+      expect(toolManager.getSummarizer).toHaveBeenCalledWith('search');
+      expect(registrySummarizer.summarizeToolReturn).toHaveBeenCalledWith(toolCall);
+      expect(result).toHaveLength(1);
+      expect(result[0].data).toEqual({ summary: 'From registry', _summary: true });
+    });
   });
 
   describe('filestore substitution', () => {
@@ -182,6 +273,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -212,6 +304,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -233,6 +326,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -263,6 +357,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -307,6 +402,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -335,6 +431,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -371,6 +468,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: false,
       });
@@ -395,6 +493,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
       });
@@ -419,6 +518,7 @@ describe('createResultTransformer', () => {
 
       const transformer = createResultTransformer({
         toolRegistry,
+        toolManager: createMockToolManager(),
         filestore,
         filestoreEnabled: true,
         tokenThreshold: 100,

x-pack/platform/plugins/shared/agent_builder/server/services/agents/modes/utils/create_result_transformer.ts

@@ -9,6 +9,7 @@ import type { ToolCallWithResult, ToolResult } from '@kbn/agent-builder-common';
 import { ToolResultType } from '@kbn/agent-builder-common';
 import type { IFileStore } from '@kbn/agent-builder-server/runner/filestore';
 import type { ToolRegistry } from '@kbn/agent-builder-server';
+import type { ToolManager } from '@kbn/agent-builder-server/runner/tool_manager';
 import { getToolCallEntryPath } from '../../../runner/store/volumes/tool_results/utils';
 
 /**
@@ -75,8 +76,16 @@ export type ToolCallResultTransformer = (toolCall: ToolCallWithResult) => Promis
 export interface CreateResultTransformerOptions {
   /**
    * Tool registry to look up tool-specific summarization functions.
+   * Used as a fallback when the tool is not found in the tool manager
+   * (e.g. for evicted dynamic tools from previous rounds).
    */
   toolRegistry: ToolRegistry;
+  /**
+   * Tool manager to look up tool-specific summarization functions.
+   * Checked first, as it contains all active tools including internal ones
+   * (filestore tools, attachment tools) that may not be in the registry.
+   */
+  toolManager: ToolManager;
   /**
    * Filestore to check token counts for file reference substitution.
    */
@@ -102,6 +111,7 @@ export interface CreateResultTransformerOptions {
  */
 export const createResultTransformer = ({
   toolRegistry,
+  toolManager,
   filestore,
   filestoreEnabled,
   tokenThreshold = FILE_REFERENCE_TOKEN_THRESHOLD,
@@ -113,7 +123,7 @@ export const createResultTransformer = ({
     }
 
     // Step 1: Try tool-specific summarization
-    const summarized = await tryToolSummarization(toolCall, toolRegistry);
+    const summarized = await tryToolSummarization(toolCall, toolManager, toolRegistry);
     if (summarized) {
       return summarized.map(markResultAsCleaned);
     }
@@ -141,12 +151,21 @@ export const createResultTransformer = ({
 
 /**
  * Attempts to apply tool-specific summarization using the tool's `summarizeToolReturn` function.
+ * Checks the tool manager first (has all active tools including internal ones like filestore tools),
+ * then falls back to the tool registry (for evicted dynamic tools from previous rounds).
  * Returns the summarized results, or undefined if no summarization is available/applicable.
  */
 const tryToolSummarization = async (
   toolCall: ToolCallWithResult,
+  toolManager: ToolManager,
   toolRegistry: ToolRegistry
 ): Promise<ToolResult[] | undefined> => {
+  const managerSummarizer = toolManager.getSummarizer(toolCall.tool_id);
+  if (managerSummarizer) {
+    const summarizedResults = managerSummarizer(toolCall);
+    return summarizedResults ?? undefined;
+  }
+
   try {
     const tool = await toolRegistry.get(toolCall.tool_id);
     if (!tool?.summarizeToolReturn) {

x-pack/platform/plugins/shared/agent_builder/server/services/agents/modes/utils/select_tools.ts

@@ -164,6 +164,7 @@ const builtinToolToExecutable = ({
     configuration: {},
     readonly: true,
     getSchema: () => tool.schema,
+    summarizeToolReturn: tool.summarizeToolReturn,
     execute: async (params) => {
       return runner.runInternalTool({
         ...params,
@@ -175,6 +176,7 @@ const builtinToolToExecutable = ({
           configuration: {},
           readonly: true,
           confirmation: { askUser: 'never' },
+          excludeFromFilestore: tool.excludeFromFilestore,
           isAvailable: async () => ({ status: 'available' as const }),
           getSchema: () => tool.schema,
           getHandler: () => tool.handler,

x-pack/platform/plugins/shared/agent_builder/server/services/runner/run_tool.ts

@@ -183,7 +183,7 @@ export const runInternalTool = async <TParams = Record<string, unknown>>({
   const afterToolHooksResult = await hooks.run(HookLifecycle.afterToolCall, postContext);
   runToolReturn = afterToolHooksResult.toolReturn;
 
-  if (runToolReturn.results) {
+  if (runToolReturn.results && !tool.excludeFromFilestore) {
     runToolReturn.results.forEach((result) => {
       resultStore.add({
         tool_id: tool.id,

x-pack/platform/plugins/shared/agent_builder/server/services/runner/store/tools/glob.ts

@@ -11,6 +11,7 @@ import { filestoreTools } from '@kbn/agent-builder-common/tools';
 import { createOtherResult } from '@kbn/agent-builder-server';
 import type { IFileStore, FileEntry } from '@kbn/agent-builder-server/runner/filestore';
 import type { BuiltinToolDefinition } from '@kbn/agent-builder-server/tools';
+import { summarizeFilestoreToolReturn } from './summarize';
 
 const schema = z.object({
   pattern: z.string().describe('Glob pattern to match files (e.g., "/**/*.json", "/logs/*.log")'),
@@ -27,6 +28,8 @@ export const globTool = ({
     type: ToolType.builtin,
     schema,
     tags: ['filestore'],
+    excludeFromFilestore: true,
+    summarizeToolReturn: summarizeFilestoreToolReturn,
     handler: async ({ pattern }, context) => {
       const entries = await filestore.glob(pattern);
       const summaries = entries.map(toSummary);