TOONify test response, not structuredContent.

Author: Piotr Paulski

src/McpResponse.ts

@@ -17,7 +17,7 @@ import type {McpContext} from './McpContext.js';
 import type {McpPage} from './McpPage.js';
 import {UncaughtError} from './PageCollector.js';
 import {TextSnapshot} from './TextSnapshot.js';
-import {DevTools, type Protocol} from './third_party/index.js';
+import {DevTools, toonEncode, type Protocol} from './third_party/index.js';
 import type {
   ConsoleMessage,
   ImageContent,
@@ -456,6 +456,7 @@ export class McpResponse implements Response {
   async handle(
     toolName: string,
     context: McpContext,
+    useToon = false,
   ): Promise<{
     content: Array<TextContent | ImageContent>;
     structuredContent: object;
@@ -674,20 +675,25 @@ export class McpResponse implements Response {
       }
     }
 
-    return this.format(toolName, context, {
-      detailedConsoleMessage,
-      consoleMessages,
-      snapshot,
-      detailedNetworkRequest,
-      networkRequests,
-      traceInsight: this.#attachedTraceInsight,
-      traceSummary: this.#attachedTraceSummary,
-      extensions,
-      lighthouseResult: this.#attachedLighthouseResult,
-      thirdPartyDeveloperTools,
-      webmcpTools,
-      errorMessage: this.#error?.message,
-    });
+    return this.format(
+      toolName,
+      context,
+      {
+        detailedConsoleMessage,
+        consoleMessages,
+        snapshot,
+        detailedNetworkRequest,
+        networkRequests,
+        traceInsight: this.#attachedTraceInsight,
+        traceSummary: this.#attachedTraceSummary,
+        extensions,
+        lighthouseResult: this.#attachedLighthouseResult,
+        thirdPartyDeveloperTools,
+        webmcpTools,
+        errorMessage: this.#error?.message,
+      },
+      useToon,
+    );
   }
 
   format(
@@ -707,6 +713,7 @@ export class McpResponse implements Response {
       webmcpTools?: WebMCPTool[];
       errorMessage?: string;
     },
+    useToon: boolean,
   ): {content: Array<TextContent | ImageContent>; structuredContent: object} {
     const structuredContent: {
       snapshot?: object;
@@ -953,9 +960,13 @@ Call ${handleDialog.name} to handle it before continuing.`);
         response.push(`Saved snapshot to ${data.snapshot}.`);
         structuredContent.snapshotFilePath = data.snapshot;
       } else {
-        response.push('## Latest page snapshot');
-        response.push(data.snapshot.toString());
         structuredContent.snapshot = data.snapshot.toJSON();
+        response.push('## Latest page snapshot');
+        response.push(
+          useToon
+            ? toonEncode(structuredContent.snapshot)
+            : data.snapshot.toString(),
+        );
       }
     }
 
@@ -988,8 +999,12 @@ Call ${handleDialog.name} to handle it before continuing.`);
         const paginatedRecord = Object.fromEntries(paginationData.items);
         const formatter = new HeapSnapshotFormatter(paginatedRecord);
 
-        response.push(formatter.toString());
         structuredContent.heapSnapshotData = formatter.toJSON();
+        response.push(
+          useToon
+            ? toonEncode(structuredContent.heapSnapshotData)
+            : formatter.toString(),
+        );
       }
       const nodes = this.#heapSnapshotOptions.nodes;
       if (nodes) {
@@ -1109,11 +1124,14 @@ Call ${handleDialog.name} to handle it before continuing.`);
         structuredContent.pagination = paginationData.pagination;
         response.push(...paginationData.info);
         if (data.networkRequests) {
-          structuredContent.networkRequests = [];
-          for (const formatter of paginationData.items) {
-            response.push(formatter.toString());
-            structuredContent.networkRequests.push(formatter.toJSON());
-          }
+          structuredContent.networkRequests = paginationData.items.map(i =>
+            i.toJSON(),
+          );
+          response.push(
+            ...(useToon
+              ? [toonEncode(structuredContent.networkRequests)]
+              : paginationData.items.map(i => i.toString())),
+          );
         }
       } else {
         response.push('No requests found.');
@@ -1131,11 +1149,15 @@ Call ${handleDialog.name} to handle it before continuing.`);
           this.#consoleDataOptions.pagination,
         );
         structuredContent.pagination = paginationData.pagination;
-        response.push(...paginationData.info);
-        response.push(...paginationData.items.map(item => item.toString()));
         structuredContent.consoleMessages = paginationData.items.map(item =>
           item.toJSON(),
         );
+        response.push(...paginationData.info);
+        if (useToon) {
+          response.push(toonEncode(structuredContent.consoleMessages));
+        } else {
+          response.push(...paginationData.items.map(item => item.toString()));
+        }
       } else {
         response.push('<no console messages found>');
       }

src/ToolHandler.ts

@@ -13,7 +13,7 @@ import {SlimMcpResponse} from './SlimMcpResponse.js';
 import {ClearcutLogger} from './telemetry/ClearcutLogger.js';
 import {bucketizeLatency} from './telemetry/transformation.js';
 import type {CallToolResult} from './third_party/index.js';
-import {zod, toonEncode} from './third_party/index.js';
+import {zod} from './third_party/index.js';
 import type {ToolCategory} from './tools/categories.js';
 import {labels, OFF_BY_DEFAULT_CATEGORIES} from './tools/categories.js';
 import type {DefinedPageTool, ToolDefinition} from './tools/ToolDefinition.js';
@@ -256,6 +256,7 @@ export class ToolHandler {
       const {content, structuredContent} = await response.handle(
         this.tool.name,
         context,
+        this.serverArgs.experimentalToonFormat ?? false,
       );
       const result: CallToolResult & {
         structuredContent?: Record<string, unknown>;
@@ -267,11 +268,7 @@ export class ToolHandler {
       }
       success = true;
       if (this.serverArgs.experimentalStructuredContent) {
-        if (this.serverArgs.experimentalStructuredContentFormat === 'toon') {
-          result.structuredContent = { format: 'toon', data: toonEncode(structuredContent)};
-        } else {
-          result.structuredContent = structuredContent as Record<string, unknown>;
-        }
+        result.structuredContent = structuredContent as Record<string, unknown>;
       }
       return result;
     } catch (err) {

src/bin/chrome-devtools-mcp-cli-options.ts

@@ -169,10 +169,10 @@ export const cliOptions = {
     type: 'boolean',
     describe: 'Whether to output structured formatted content.',
   },
-  experimentalStructuredContentFormat: {
-    type: 'string',
-    describe: 'The format of the structured content. Defaults to "json".',
-    choices: ['toon', 'json'] as const,
+  experimentalToonFormat: {
+    type: 'boolean',
+    describe:
+      'Whether to format structured data in text response using Token-Oriented Object Notation. Defaults to false which represents the embedded content as formatted JSON instead.',
     hidden: true,
   },
   experimentalIncludeAllPages: {
@@ -316,20 +316,6 @@ export function parseArguments(
         );
         args.usageStatistics = false;
       }
-      if (args.experimentalStructuredContentFormat && args.experimentalStructuredContent === undefined) {
-        args.experimentalStructuredContent = true;
-      }
-      if (args.experimentalStructuredContentFormat === undefined && args.experimentalStructuredContent) {
-        args.experimentalStructuredContentFormat = 'json';
-      }
-    })
-    .check(args => {
-      if (args.experimentalStructuredContentFormat && !args.experimentalStructuredContent) {
-        throw new Error(
-          'The --experimentalStructuredContentFormat option can only be used when --experimentalStructuredContent is enabled.'
-        );
-      }
-      return true;
     })
     .example([
       [

src/telemetry/flag_usage_metrics.json

@@ -295,5 +295,13 @@
   {
     "name": "category_experimental_third_party",
     "flagType": "boolean"
+  },
+  {
+    "name": "experimental_toon_format_present",
+    "flagType": "boolean"
+  },
+  {
+    "name": "experimental_toon_format",
+    "flagType": "boolean"
   }
 ]