Fix linting errors in a number of core and tool files (partial)

- As part of this work I also started building out errors.ts which will be a cumulation of error helpers to better handle the challenging `catch (error: unknown)` requirement.
- More changes are to come, this is truly a partial change in order to not disrupt as many people as possible.

Part of https://b.corp.google.com/issues/411384603

9 files changed, 62 insertions, 62 deletions

diff --git a/packages/cli/src/core/gemini-client.ts b/packages/cli/src/core/gemini-client.ts
index 0b79a2ad..21cc7188 100644
--- a/packages/cli/src/core/gemini-client.ts
+++ b/packages/cli/src/core/gemini-client.ts
@@ -25,9 +25,9 @@ import { GeminiEventType, GeminiStream } from './gemini-stream.js';
 type ToolExecutionOutcome = {
   callId: string;
   name: string;
-  args: Record<string, any>;
+  args: Record<string, never>;
   result?: ToolResult;
-  error?: any;
+  error?: Error;
   confirmationDetails?: ToolCallConfirmationDetails;
 };
 
@@ -126,7 +126,7 @@ ${folderStructure}
         let pendingToolCalls: Array<{
           callId: string;
           name: string;
-          args: Record<string, any>;
+          args: Record<string, never>;
         }> = [];
         let yieldedTextInTurn = false;
         const chunksForDebug = [];
@@ -148,7 +148,7 @@ ${folderStructure}
                 call.id ??
                 `${call.name}-${Date.now()}-${Math.random().toString(16).slice(2)}`;
               const name = call.name || 'undefined_tool_name';
-              const args = (call.args || {}) as Record<string, any>;
+              const args = (call.args || {}) as Record<string, never>;
 
               pendingToolCalls.push({ callId, name, args });
               const evtValue: ToolCallEvent = {
@@ -281,7 +281,7 @@ ${folderStructure}
             (executedTool: ToolExecutionOutcome): Part => {
               const { name, result, error } = executedTool;
               const output = { output: result?.llmContent };
-              let toolOutcomePayload: any;
+              let toolOutcomePayload: Record<string, unknown>;
 
               if (error) {
                 const errorMessage = error?.message || String(error);
@@ -445,11 +445,11 @@ Respond *only* in JSON format according to the following schema. Do not include
   async generateJson(
     contents: Content[],
     schema: SchemaUnion,
-  ): Promise<any> {
+  ): Promise<Record<string, unknown>> {
     const model = getModel();
     try {
       const result = await this.ai.models.generateContent({
-        model: model,
+        model,
         config: {
           ...this.defaultHyperParameters,
           systemInstruction: CoreSystemPrompt,
diff --git a/packages/cli/src/core/gemini-stream.ts b/packages/cli/src/core/gemini-stream.ts
index 314a829d..70361f10 100644
--- a/packages/cli/src/core/gemini-stream.ts
+++ b/packages/cli/src/core/gemini-stream.ts
@@ -154,14 +154,14 @@ export const processGeminiStream = async ({
     if (signal.aborted) {
       throw new Error('Request cancelled by user');
     }
-  } catch (error: any) {
+  } catch (error: unknown) {
     if (renderTimeoutId) {
       // Ensure render loop stops on error
       clearTimeout(renderTimeoutId);
       renderTimeoutId = null;
     }
     // Delegate history update for error message
-    addErrorMessageToHistory(error, setHistory, getNextMessageId);
+    addErrorMessageToHistory(error as (Error | DOMException), setHistory, getNextMessageId);
   } finally {
     isStreamComplete = true; // Signal stream end for render loop completion
     if (renderTimeoutId) {
diff --git a/packages/cli/src/core/history-updater.ts b/packages/cli/src/core/history-updater.ts
index a97c99a1..465b7d49 100644
--- a/packages/cli/src/core/history-updater.ts
+++ b/packages/cli/src/core/history-updater.ts
@@ -178,7 +178,7 @@ export const handleToolCallChunk = (
  * it to the last non-user message or creating a new entry.
  */
 export const addErrorMessageToHistory = (
-  error: any,
+  error: DOMException | Error,
   setHistory: React.Dispatch<React.SetStateAction<HistoryItem[]>>,
   getNextMessageId: () => number,
 ): void => {
diff --git a/packages/cli/src/tools/edit.tool.ts b/packages/cli/src/tools/edit.tool.ts
index a98b9861..de8ccd5b 100644
--- a/packages/cli/src/tools/edit.tool.ts
+++ b/packages/cli/src/tools/edit.tool.ts
@@ -11,6 +11,7 @@ import {
 import { makeRelative, shortenPath } from '../utils/paths.js';
 import { ReadFileTool } from './read-file.tool.js';
 import { WriteFileTool } from './write-file.tool.js';
+import { isNodeError } from '../utils/errors.js';
 
 /**
  * Parameters for the Edit tool
@@ -37,11 +38,6 @@ export interface EditToolParams {
   expected_replacements?: number;
 }
 
-/**
- * Result from the Edit tool
- */
-export interface EditToolResult extends ToolResult {}
-
 interface CalculatedEdit {
   currentContent: string | null;
   newContent: string;
@@ -54,7 +50,7 @@ interface CalculatedEdit {
  * Implementation of the Edit tool that modifies files.
  * This tool maintains state for the "Always Edit" confirmation preference.
  */
-export class EditTool extends BaseTool<EditToolParams, EditToolResult> {
+export class EditTool extends BaseTool<EditToolParams, ToolResult> {
   private shouldAlwaysEdit = false;
   private readonly rootDirectory: string;
 
@@ -174,8 +170,8 @@ export class EditTool extends BaseTool<EditToolParams, EditToolResult> {
     try {
       currentContent = fs.readFileSync(params.file_path, 'utf8');
       fileExists = true;
-    } catch (err: any) {
-      if (err.code !== 'ENOENT') {
+    } catch (err: unknown) {
+      if (!isNodeError(err) || err.code !== 'ENOENT') {
         throw err;
       }
       fileExists = false;
@@ -300,7 +296,7 @@ export class EditTool extends BaseTool<EditToolParams, EditToolResult> {
    * @param params Parameters for the edit operation
    * @returns Result of the edit operation
    */
-  async execute(params: EditToolParams): Promise<EditToolResult> {
+  async execute(params: EditToolParams): Promise<ToolResult> {
     if (!this.validateParams(params)) {
       return {
         llmContent: 'Invalid parameters for file edit operation',
diff --git a/packages/cli/src/tools/glob.tool.ts b/packages/cli/src/tools/glob.tool.ts
index 6c14b7d1..d9d82210 100644
--- a/packages/cli/src/tools/glob.tool.ts
+++ b/packages/cli/src/tools/glob.tool.ts
@@ -21,15 +21,10 @@ export interface GlobToolParams {
 }
 
 /**
- * Result from the GlobTool
- */
-export interface GlobToolResult extends ToolResult {}
-
-/**
  * Implementation of the GlobTool that finds files matching patterns,
  * sorted by modification time (newest first).
  */
-export class GlobTool extends BaseTool<GlobToolParams, GlobToolResult> {
+export class GlobTool extends BaseTool<GlobToolParams, ToolResult> {
   /**
    * The root directory that this tool is grounded in.
    * All file operations will be restricted to this directory.
@@ -125,9 +120,9 @@ export class GlobTool extends BaseTool<GlobToolParams, GlobToolResult> {
       if (!fs.statSync(searchDirAbsolute).isDirectory()) {
         return `Search path is not a directory: ${shortenPath(makeRelative(searchDirAbsolute, this.rootDirectory))} (absolute: ${searchDirAbsolute})`;
       }
-    } catch (e: any) {
+    } catch (e: unknown) {
       // Catch potential permission errors during sync checks
-      return `Error accessing search path: ${e.message}`;
+      return `Error accessing search path: ${e}`;
     }
 
     // Validate glob pattern (basic non-empty check)
@@ -165,7 +160,7 @@ export class GlobTool extends BaseTool<GlobToolParams, GlobToolResult> {
    * @param params Parameters for the glob search
    * @returns Result of the glob search
    */
-  async execute(params: GlobToolParams): Promise<GlobToolResult> {
+  async execute(params: GlobToolParams): Promise<ToolResult> {
     const validationError = this.invalidParams(params);
     if (validationError) {
       return {
diff --git a/packages/cli/src/tools/grep.tool.ts b/packages/cli/src/tools/grep.tool.ts
index 788fc76d..1c334a09 100644
--- a/packages/cli/src/tools/grep.tool.ts
+++ b/packages/cli/src/tools/grep.tool.ts
@@ -7,6 +7,7 @@ import fastGlob from 'fast-glob'; // Used for JS fallback file searching
 import { BaseTool, ToolResult } from './tools.js';
 import { SchemaValidator } from '../utils/schemaValidator.js';
 import { makeRelative, shortenPath } from '../utils/paths.js';
+import { getErrorMessage, isNodeError } from '../utils/errors.js';
 
 // --- Interfaces (kept separate for clarity) ---
 
@@ -39,17 +40,12 @@ interface GrepMatch {
   line: string;
 }
 
-/**
- * Result from the GrepTool
- */
-export interface GrepToolResult extends ToolResult {}
-
 // --- GrepTool Class ---
 
 /**
  * Implementation of the GrepTool that searches file contents using git grep, system grep, or JS fallback.
  */
-export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
+export class GrepTool extends BaseTool<GrepToolParams, ToolResult> {
   private rootDirectory: string;
 
   /**
@@ -114,12 +110,12 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
       if (!stats.isDirectory()) {
         throw new Error(`Path is not a directory: ${targetPath}`);
       }
-    } catch (err: any) {
-      if (err.code === 'ENOENT') {
+    } catch (error: unknown) {
+      if (isNodeError(error) && error.code !== 'ENOENT') {
         throw new Error(`Path does not exist: ${targetPath}`);
       }
       throw new Error(
-        `Failed to access path stats for ${targetPath}: ${err.message}`,
+        `Failed to access path stats for ${targetPath}: ${error}`,
       );
     }
 
@@ -164,7 +160,7 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
    * @param params Parameters for the grep search
    * @returns Result of the grep search
    */
-  async execute(params: GrepToolParams): Promise<GrepToolResult> {
+  async execute(params: GrepToolParams): Promise<ToolResult> {
     const validationError = this.invalidParams(params);
     if (validationError) {
       console.error(`GrepTool Parameter Validation Failed: ${validationError}`);
@@ -253,7 +249,7 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
         });
         child.on('close', (code) => resolve(code === 0));
         child.on('error', () => resolve(false));
-      } catch (e) {
+      } catch {
         resolve(false);
       }
     });
@@ -277,10 +273,10 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
             return true;
           }
           return false;
-        } catch (err: any) {
-          if (err.code !== 'ENOENT') {
+        } catch (error: unknown) {
+          if (!isNodeError(error) || error.code !== 'ENOENT') {
             console.error(
-              `Error checking for .git in ${currentPath}: ${err.message}`,
+              `Error checking for .git in ${currentPath}: ${error}`,
             );
             return false;
           }
@@ -291,9 +287,9 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
         }
         currentPath = path.dirname(currentPath);
       }
-    } catch (err: any) {
+    } catch (error: unknown) {
       console.error(
-        `Error traversing directory structure upwards from ${dirPath}: ${err instanceof Error ? err.message : String(err)}`,
+        `Error traversing directory structure upwards from ${dirPath}: ${error instanceof Error ? error.message : error}`,
       );
     }
     return false;
@@ -446,9 +442,9 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
             });
           });
           return this.parseGrepOutput(output, absolutePath);
-        } catch (gitError: any) {
+        } catch (gitError: unknown) {
           console.error(
-            `GrepTool: git grep strategy failed: ${gitError.message}. Falling back...`,
+            `GrepTool: git grep strategy failed: ${getErrorMessage(gitError)}. Falling back...`,
           );
         }
       }
@@ -512,9 +508,9 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
             });
           });
           return this.parseGrepOutput(output, absolutePath);
-        } catch (grepError: any) {
+        } catch (grepError: unknown) {
           console.error(
-            `GrepTool: System grep strategy failed: ${grepError.message}. Falling back...`,
+            `GrepTool: System grep strategy failed: ${getErrorMessage(grepError)}. Falling back...`,
           );
         }
       }
@@ -559,19 +555,19 @@ export class GrepTool extends BaseTool<GrepToolParams, GrepToolResult> {
               });
             }
           });
-        } catch (readError: any) {
-          if (readError.code !== 'ENOENT') {
+        } catch (readError: unknown) {
+          if (!isNodeError(readError) || readError.code !== 'ENOENT') {
             console.error(
-              `GrepTool: Could not read or process file ${fileAbsolutePath}: ${readError.message}`,
+              `GrepTool: Could not read or process file ${fileAbsolutePath}: ${getErrorMessage(readError)}`,
             );
           }
         }
       }
 
       return allMatches;
-    } catch (error: any) {
+    } catch (error: unknown) {
       console.error(
-        `GrepTool: Error during performGrepSearch (Strategy: ${strategyUsed}): ${error.message}`,
+        `GrepTool: Error during performGrepSearch (Strategy: ${strategyUsed}): ${getErrorMessage(error)}`,
       );
       throw error; // Re-throw to be caught by the execute method's handler
     }
diff --git a/packages/cli/src/tools/read-file.tool.ts b/packages/cli/src/tools/read-file.tool.ts
index 98df7c12..9737e75d 100644
--- a/packages/cli/src/tools/read-file.tool.ts
+++ b/packages/cli/src/tools/read-file.tool.ts
@@ -25,16 +25,11 @@ export interface ReadFileToolParams {
 }
 
 /**
- * Standardized result from the ReadFile tool
- */
-export interface ReadFileToolResult extends ToolResult {}
-
-/**
  * Implementation of the ReadFile tool that reads files from the filesystem
  */
 export class ReadFileTool extends BaseTool<
   ReadFileToolParams,
-  ReadFileToolResult
+  ToolResult
 > {
   static readonly Name: string = 'read_file';
 
@@ -166,7 +161,7 @@ export class ReadFileTool extends BaseTool<
 
       // If more than 30% are non-printable, likely binary
       return nonPrintableCount / bytesRead > 0.3;
-    } catch (error) {
+    } catch {
       return false;
     }
   }
@@ -214,7 +209,7 @@ export class ReadFileTool extends BaseTool<
    * @param params Parameters for the file reading
    * @returns Result with file contents
    */
-  async execute(params: ReadFileToolParams): Promise<ReadFileToolResult> {
+  async execute(params: ReadFileToolParams): Promise<ToolResult> {
     const validationError = this.invalidParams(params);
     const filePath = params.file_path;
     if (validationError) {
diff --git a/packages/cli/src/ui/types.ts b/packages/cli/src/ui/types.ts
index 320f355b..78031a25 100644
--- a/packages/cli/src/ui/types.ts
+++ b/packages/cli/src/ui/types.ts
@@ -12,7 +12,7 @@ export interface ToolCallEvent {
   status: ToolCallStatus;
   callId: string;
   name: string;
-  args: Record<string, any>;
+  args: Record<string, never>;
   resultDisplay: ToolResultDisplay | undefined;
   confirmationDetails: ToolCallConfirmationDetails | undefined;
 }
diff --git a/packages/cli/src/utils/errors.ts b/packages/cli/src/utils/errors.ts
new file mode 100644
index 00000000..7708895a
--- /dev/null
+++ b/packages/cli/src/utils/errors.ts
@@ -0,0 +1,18 @@
+export function isNodeError(error: unknown): error is NodeJS.ErrnoException {
+    return error instanceof Error && 'code' in error;
+}
+
+export function getErrorMessage(error: unknown): string {
+    if (error instanceof Error) {
+        return error.message;
+      } else {
+        // Attempt to convert the non-Error value to a string for logging
+        try {
+           const errorMessage = String(error);
+           return errorMessage;
+        } catch {
+            // If String() itself fails (highly unlikely)
+            return 'Failed to get error details';
+        }
+      }
+}
\ No newline at end of file