fix: switch system prompt to avoid malformed tool_calls (#650)

* fix: switch system prompt to avoid malformed tool_calls

* fix: circular dependency issue and configurable tool-call style

* fix: regExp issue

packages/core/src/tools/edit.ts

@@ -24,6 +24,7 @@ import { ApprovalMode } from '../config/config.js';
 import { ensureCorrectEdit } from '../utils/editCorrector.js';
 import { DEFAULT_DIFF_OPTIONS, getDiffStat } from './diffOptions.js';
 import { ReadFileTool } from './read-file.js';
+import { ToolNames } from './tool-names.js';
 import type {
   ModifiableDeclarativeTool,
   ModifyContext,
@@ -461,7 +462,7 @@ export class EditTool
   extends BaseDeclarativeTool<EditToolParams, ToolResult>
   implements ModifiableDeclarativeTool<EditToolParams>
 {
-  static readonly Name = 'edit';
+  static readonly Name = ToolNames.EDIT;
   constructor(private readonly config: Config) {
     super(
       EditTool.Name,

packages/core/src/tools/glob.ts

@@ -9,6 +9,7 @@ import path from 'node:path';
 import { glob, escape } from 'glob';
 import type { ToolInvocation, ToolResult } from './tools.js';
 import { BaseDeclarativeTool, BaseToolInvocation, Kind } from './tools.js';
+import { ToolNames } from './tool-names.js';
 import { shortenPath, makeRelative } from '../utils/paths.js';
 import type { Config } from '../config/config.js';
 import { ToolErrorType } from './tool-error.js';
@@ -252,7 +253,7 @@ class GlobToolInvocation extends BaseToolInvocation<
  * Implementation of the Glob tool logic
  */
 export class GlobTool extends BaseDeclarativeTool<GlobToolParams, ToolResult> {
-  static readonly Name = 'glob';
+  static readonly Name = ToolNames.GLOB;
 
   constructor(private config: Config) {
     super(

packages/core/src/tools/grep.ts

@@ -12,6 +12,7 @@ import { spawn } from 'node:child_process';
 import { globStream } from 'glob';
 import type { ToolInvocation, ToolResult } from './tools.js';
 import { BaseDeclarativeTool, BaseToolInvocation, Kind } from './tools.js';
+import { ToolNames } from './tool-names.js';
 import { makeRelative, shortenPath } from '../utils/paths.js';
 import { getErrorMessage, isNodeError } from '../utils/errors.js';
 import { isGitRepository } from '../utils/gitUtils.js';
@@ -597,7 +598,7 @@ class GrepToolInvocation extends BaseToolInvocation<
  * Implementation of the Grep tool logic (moved from CLI)
  */
 export class GrepTool extends BaseDeclarativeTool<GrepToolParams, ToolResult> {
-  static readonly Name = 'search_file_content'; // Keep static name
+  static readonly Name = ToolNames.GREP;
 
   constructor(private readonly config: Config) {
     super(

packages/core/src/tools/read-file.ts

@@ -8,6 +8,7 @@ import path from 'node:path';
 import { makeRelative, shortenPath } from '../utils/paths.js';
 import type { ToolInvocation, ToolLocation, ToolResult } from './tools.js';
 import { BaseDeclarativeTool, BaseToolInvocation, Kind } from './tools.js';
+import { ToolNames } from './tool-names.js';
 
 import type { PartUnion } from '@google/genai';
 import {
@@ -136,7 +137,7 @@ export class ReadFileTool extends BaseDeclarativeTool<
   ReadFileToolParams,
   ToolResult
 > {
-  static readonly Name: string = 'read_file';
+  static readonly Name: string = ToolNames.READ_FILE;
 
   constructor(private config: Config) {
     super(

packages/core/src/tools/read-many-files.ts

@@ -6,6 +6,7 @@
 
 import type { ToolInvocation, ToolResult } from './tools.js';
 import { BaseDeclarativeTool, BaseToolInvocation, Kind } from './tools.js';
+import { ToolNames } from './tool-names.js';
 import { getErrorMessage } from '../utils/errors.js';
 import * as fs from 'node:fs';
 import * as path from 'node:path';
@@ -526,7 +527,7 @@ export class ReadManyFilesTool extends BaseDeclarativeTool<
   ReadManyFilesParams,
   ToolResult
 > {
-  static readonly Name: string = 'read_many_files';
+  static readonly Name: string = ToolNames.READ_MANY_FILES;
 
   constructor(private config: Config) {
     const parameterSchema = {

packages/core/src/tools/shell.ts

@@ -9,6 +9,7 @@ import path from 'node:path';
 import os, { EOL } from 'node:os';
 import crypto from 'node:crypto';
 import type { Config } from '../config/config.js';
+import { ToolNames } from './tool-names.js';
 import { ToolErrorType } from './tool-error.js';
 import type {
   ToolInvocation,
@@ -403,7 +404,7 @@ export class ShellTool extends BaseDeclarativeTool<
   ShellToolParams,
   ToolResult
 > {
-  static Name: string = 'run_shell_command';
+  static Name: string = ToolNames.SHELL;
   private allowlist: Set<string> = new Set();
 
   constructor(private readonly config: Config) {

packages/core/src/tools/task.ts

@@ -5,6 +5,7 @@
  */
 
 import { BaseDeclarativeTool, BaseToolInvocation, Kind } from './tools.js';
+import { ToolNames } from './tool-names.js';
 import type {
   ToolResult,
   ToolResultDisplay,
@@ -46,7 +47,7 @@ export interface TaskParams {
  * for the model to choose from.
  */
 export class TaskTool extends BaseDeclarativeTool<TaskParams, ToolResult> {
-  static readonly Name: string = 'task';
+  static readonly Name: string = ToolNames.TASK;
 
   private subagentManager: SubagentManager;
   private availableSubagents: SubagentConfig[] = [];

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

@@ -0,0 +1,23 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Tool name constants to avoid circular dependencies.
+ * These constants are used across multiple files and should be kept in sync
+ * with the actual tool class names.
+ */
+export const ToolNames = {
+  EDIT: 'edit',
+  WRITE_FILE: 'write_file',
+  READ_FILE: 'read_file',
+  READ_MANY_FILES: 'read_many_files',
+  GREP: 'search_file_content',
+  GLOB: 'glob',
+  SHELL: 'run_shell_command',
+  TODO_WRITE: 'todo_write',
+  MEMORY: 'save_memory',
+  TASK: 'task',
+} as const;

packages/core/src/tools/write-file.ts

@@ -31,6 +31,7 @@ import {
   ensureCorrectFileContent,
 } from '../utils/editCorrector.js';
 import { DEFAULT_DIFF_OPTIONS, getDiffStat } from './diffOptions.js';
+import { ToolNames } from './tool-names.js';
 import type {
   ModifiableDeclarativeTool,
   ModifyContext,
@@ -403,7 +404,7 @@ export class WriteFileTool
   extends BaseDeclarativeTool<WriteFileToolParams, ToolResult>
   implements ModifiableDeclarativeTool<WriteFileToolParams>
 {
-  static readonly Name: string = 'write_file';
+  static readonly Name: string = ToolNames.WRITE_FILE;
 
   constructor(private readonly config: Config) {
     super(