Summarize tool call outputs using tool specific summarizers (#3745)

packages/core/src/tools/shell.ts

@@ -27,6 +27,7 @@ export interface ShellToolParams {
   directory?: string;
 }
 import { spawn } from 'child_process';
+import { llmSummarizer } from '../utils/summarizer.js';
 
 const OUTPUT_UPDATE_INTERVAL_MS = 1000;
 
@@ -73,6 +74,8 @@ Process Group PGID: Process group started or \`(none)\``,
       },
       false, // output is not markdown
       true, // output can be updated
+      llmSummarizer,
+      true, // should summarize display output
     );
   }
 
@@ -487,7 +490,6 @@ Process Group PGID: Process group started or \`(none)\``,
         // returnDisplayMessage will remain empty, which is fine.
       }
     }
-
     return { llmContent, returnDisplay: returnDisplayMessage };
   }
 }

packages/core/src/tools/tool-registry.ts

@@ -11,6 +11,7 @@ import { spawn } from 'node:child_process';
 import { StringDecoder } from 'node:string_decoder';
 import { discoverMcpTools } from './mcp-client.js';
 import { DiscoveredMCPTool } from './mcp-tool.js';
+import { defaultSummarizer } from '../utils/summarizer.js';
 import { parse } from 'shell-quote';
 
 type ToolParams = Record<string, unknown>;
@@ -47,6 +48,7 @@ Signal: Signal number or \`(none)\` if no signal was received.
       parameterSchema,
       false, // isOutputMarkdown
       false, // canUpdateOutput
+      defaultSummarizer,
     );
   }
 

packages/core/src/tools/tools.ts

@@ -5,6 +5,7 @@
  */
 
 import { FunctionDeclaration, PartListUnion, Schema } from '@google/genai';
+import { Summarizer, defaultSummarizer } from '../utils/summarizer.js';
 
 /**
  * Interface representing the base Tool functionality
@@ -43,6 +44,16 @@ export interface Tool<
    */
   canUpdateOutput: boolean;
 
+  /**
+   * A function that summarizes the result of the tool execution.
+   */
+  summarizer?: Summarizer;
+
+  /**
+   * Whether the tool's display output should be summarized
+   */
+  shouldSummarizeDisplay?: boolean;
+
   /**
    * Validates the parameters for the tool
    * Should be called from both `shouldConfirmExecute` and `execute`
@@ -98,6 +109,8 @@ export abstract class BaseTool<
    * @param isOutputMarkdown Whether the tool's output should be rendered as markdown
    * @param canUpdateOutput Whether the tool supports live (streaming) output
    * @param parameterSchema JSON Schema defining the parameters
+   * @param summarizer Function to summarize the tool's output
+   * @param shouldSummarizeDisplay Whether the tool's display output should be summarized
    */
   constructor(
     readonly name: string,
@@ -106,6 +119,8 @@ export abstract class BaseTool<
     readonly parameterSchema: Schema,
     readonly isOutputMarkdown: boolean = true,
     readonly canUpdateOutput: boolean = false,
+    readonly summarizer: Summarizer = defaultSummarizer,
+    readonly shouldSummarizeDisplay: boolean = false,
   ) {}
 
   /**
@@ -173,6 +188,11 @@ export abstract class BaseTool<
 }
 
 export interface ToolResult {
+  /**
+   * A short, one-line summary of the tool's action and result.
+   * e.g., "Read 5 files", "Wrote 256 bytes to foo.txt"
+   */
+  summary?: string;
   /**
    * Content meant to be included in LLM history.
    * This should represent the factual outcome of the tool execution.