fix: Strip ANSI color sequences from tool output

Add stripAnsiCodes function to sanitizer and apply it in formatResultContent
to remove terminal color escape codes (e.g., [1;33m for yellow/bold) from
tool output before displaying it in GitHub comments.

This ensures clean, readable output without raw ANSI escape sequences
appearing in the formatted tool results.

.github/workflows/sync-base-action.yml

@@ -94,5 +94,5 @@ jobs:
           echo "✅ Successfully synced \`base-action\` directory to [anthropics/claude-code-base-action](https://github.com/anthropics/claude-code-base-action)" >> $GITHUB_STEP_SUMMARY
           echo "" >> $GITHUB_STEP_SUMMARY
           echo "- **Source commit**: [\`${GITHUB_SHA:0:7}\`](https://github.com/anthropics/claude-code-action/commit/${GITHUB_SHA})" >> $GITHUB_STEP_SUMMARY
-          echo "- **Triggered by**: ${{ github.event_name }}" >> $GITHUB_STEP_SUMMARY
-          echo "- **Actor**: @${{ github.actor }}" >> $GITHUB_STEP_SUMMARY
+          echo "- **Triggered by**: $GITHUB_EVENT_NAME" >> $GITHUB_STEP_SUMMARY
+          echo "- **Actor**: @$GITHUB_ACTOR" >> $GITHUB_STEP_SUMMARY

action.yml

@@ -140,10 +140,12 @@ runs:
     - name: Setup Custom Bun Path
       if: inputs.path_to_bun_executable != ''
       shell: bash
+      env:
+        PATH_TO_BUN_EXECUTABLE: ${{ inputs.path_to_bun_executable }}
       run: |
-        echo "Using custom Bun executable: ${{ inputs.path_to_bun_executable }}"
+        echo "Using custom Bun executable: $PATH_TO_BUN_EXECUTABLE"
         # Add the directory containing the custom executable to PATH
-        BUN_DIR=$(dirname "${{ inputs.path_to_bun_executable }}")
+        BUN_DIR=$(dirname "$PATH_TO_BUN_EXECUTABLE")
         echo "$BUN_DIR" >> "$GITHUB_PATH"
 
     - name: Install Dependencies
@@ -182,6 +184,8 @@ runs:
     - name: Install Base Action Dependencies
       if: steps.prepare.outputs.contains_trigger == 'true'
       shell: bash
+      env:
+        PATH_TO_CLAUDE_CODE_EXECUTABLE: ${{ inputs.path_to_claude_code_executable }}
       run: |
         echo "Installing base-action dependencies..."
         cd ${GITHUB_ACTION_PATH}/base-action
@@ -190,8 +194,8 @@ runs:
         cd -
 
         # Install Claude Code if no custom executable is provided
-        if [ -z "${{ inputs.path_to_claude_code_executable }}" ]; then
-          CLAUDE_CODE_VERSION="2.0.60"
+        if [ -z "$PATH_TO_CLAUDE_CODE_EXECUTABLE" ]; then
+          CLAUDE_CODE_VERSION="2.0.62"
           echo "Installing Claude Code v${CLAUDE_CODE_VERSION}..."
           for attempt in 1 2 3; do
             echo "Installation attempt $attempt..."
@@ -210,9 +214,9 @@ runs:
           echo "Claude Code installed successfully"
           echo "$HOME/.local/bin" >> "$GITHUB_PATH"
         else
-          echo "Using custom Claude Code executable: ${{ inputs.path_to_claude_code_executable }}"
+          echo "Using custom Claude Code executable: $PATH_TO_CLAUDE_CODE_EXECUTABLE"
           # Add the directory containing the custom executable to PATH
-          CLAUDE_DIR=$(dirname "${{ inputs.path_to_claude_code_executable }}")
+          CLAUDE_DIR=$(dirname "$PATH_TO_CLAUDE_CODE_EXECUTABLE")
           echo "$CLAUDE_DIR" >> "$GITHUB_PATH"
         fi
 

base-action/action.yml

@@ -101,10 +101,12 @@ runs:
     - name: Setup Custom Bun Path
       if: inputs.path_to_bun_executable != ''
       shell: bash
+      env:
+        PATH_TO_BUN_EXECUTABLE: ${{ inputs.path_to_bun_executable }}
       run: |
-        echo "Using custom Bun executable: ${{ inputs.path_to_bun_executable }}"
+        echo "Using custom Bun executable: $PATH_TO_BUN_EXECUTABLE"
         # Add the directory containing the custom executable to PATH
-        BUN_DIR=$(dirname "${{ inputs.path_to_bun_executable }}")
+        BUN_DIR=$(dirname "$PATH_TO_BUN_EXECUTABLE")
         echo "$BUN_DIR" >> "$GITHUB_PATH"
 
     - name: Install Dependencies
@@ -115,9 +117,11 @@ runs:
 
     - name: Install Claude Code
       shell: bash
+      env:
+        PATH_TO_CLAUDE_CODE_EXECUTABLE: ${{ inputs.path_to_claude_code_executable }}
       run: |
-        if [ -z "${{ inputs.path_to_claude_code_executable }}" ]; then
-          CLAUDE_CODE_VERSION="2.0.60"
+        if [ -z "$PATH_TO_CLAUDE_CODE_EXECUTABLE" ]; then
+          CLAUDE_CODE_VERSION="2.0.62"
           echo "Installing Claude Code v${CLAUDE_CODE_VERSION}..."
           for attempt in 1 2 3; do
             echo "Installation attempt $attempt..."
@@ -135,9 +139,9 @@ runs:
           done
           echo "Claude Code installed successfully"
         else
-          echo "Using custom Claude Code executable: ${{ inputs.path_to_claude_code_executable }}"
+          echo "Using custom Claude Code executable: $PATH_TO_CLAUDE_CODE_EXECUTABLE"
           # Add the directory containing the custom executable to PATH
-          CLAUDE_DIR=$(dirname "${{ inputs.path_to_claude_code_executable }}")
+          CLAUDE_DIR=$(dirname "$PATH_TO_CLAUDE_CODE_EXECUTABLE")
           echo "$CLAUDE_DIR" >> "$GITHUB_PATH"
         fi
 

base-action/src/run-claude-sdk.ts

@@ -75,28 +75,15 @@ export async function runClaudeWithSdk(
   }
 
   console.log(`Running Claude with prompt from file: ${promptPath}`);
-  console.log(
-    "[DEBUG] Prompt content (first 2000 chars):",
-    prompt.substring(0, 2000),
-  );
-  console.log("[DEBUG] Prompt length:", prompt.length);
-  console.log(
-    "[DEBUG] sdkOptions passed to query():",
-    JSON.stringify(sdkOptions, null, 2),
-  );
+  // Log SDK options without env (which could contain sensitive data)
+  const { env, ...optionsToLog } = sdkOptions;
+  console.log("SDK options:", JSON.stringify(optionsToLog, null, 2));
 
   const messages: SDKMessage[] = [];
   let resultMessage: SDKResultMessage | undefined;
 
   try {
-    console.log("[DEBUG] About to call query()...");
     for await (const message of query({ prompt, options: sdkOptions })) {
-      console.log(
-        "[DEBUG] Received message type:",
-        message.type,
-        "subtype:",
-        (message as any).subtype,
-      );
       messages.push(message);
 
       const sanitized = sanitizeSdkOutput(message, showFullOutput);
@@ -106,16 +93,8 @@ export async function runClaudeWithSdk(
 
       if (message.type === "result") {
         resultMessage = message as SDKResultMessage;
-        console.log(
-          "[DEBUG] Got result message:",
-          JSON.stringify(resultMessage, null, 2),
-        );
       }
     }
-    console.log(
-      "[DEBUG] Finished iterating query(), total messages:",
-      messages.length,
-    );
   } catch (error) {
     console.error("SDK execution error:", error);
     core.setOutput("conclusion", "failure");

base-action/src/run-claude.ts

@@ -174,15 +174,7 @@ export async function runClaude(promptPath: string, options: ClaudeOptions) {
   );
 
   if (useAgentSdk) {
-    console.log(
-      "[DEBUG] Raw options passed to SDK path:",
-      JSON.stringify(options, null, 2),
-    );
     const parsedOptions = parseSdkOptions(options);
-    console.log(
-      "[DEBUG] Parsed SDK options:",
-      JSON.stringify(parsedOptions, null, 2),
-    );
     return runClaudeWithSdk(promptPath, parsedOptions);
   }
 

src/entrypoints/format-turns.ts

@@ -2,6 +2,7 @@
 
 import { readFileSync, existsSync } from "fs";
 import { exit } from "process";
+import { stripAnsiCodes } from "../github/utils/sanitizer";
 
 export type ToolUse = {
   type: string;
@@ -172,6 +173,9 @@ export function formatResultContent(content: any): string {
     contentStr = String(content).trim();
   }
 
+  // Strip ANSI escape codes from terminal output
+  contentStr = stripAnsiCodes(contentStr);
+
   // Truncate very long results
   if (contentStr.length > 3000) {
     contentStr = contentStr.substring(0, 2997) + "...";

src/github/utils/sanitizer.ts

@@ -1,3 +1,11 @@
+export function stripAnsiCodes(content: string): string {
+  // Matches ANSI escape sequences:
+  // - \x1B[ (CSI) followed by parameters and a final byte
+  // - \x1B followed by single-character sequences
+  // Common sequences: \x1B[1;33m (colors), \x1B[0m (reset), \x1B[K (clear line)
+  return content.replace(/\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])/g, "");
+}
+
 export function stripInvisibleCharacters(content: string): string {
   content = content.replace(/[\u200B\u200C\u200D\uFEFF]/g, "");
   content = content.replace(

test/format-turns.test.ts

@@ -111,6 +111,27 @@ describe("formatResultContent", () => {
     const result = formatResultContent(JSON.stringify(structuredContent));
     expect(result).toBe("**→** Hello world\n\n");
   });
+
+  test("strips ANSI color codes from terminal output", () => {
+    // Test bold yellow warning (the issue reported: [1;33m)
+    const coloredOutput = "\x1B[1;33mWarning: something happened\x1B[0m";
+    const result = formatResultContent(coloredOutput);
+    expect(result).toBe("**→** Warning: something happened\n\n");
+    expect(result).not.toContain("\x1B");
+    expect(result).not.toContain("[1;33m");
+  });
+
+  test("strips ANSI codes from longer output in code blocks", () => {
+    const longColoredOutput =
+      "\x1B[32m✓\x1B[0m Test 1 passed\n" +
+      "\x1B[32m✓\x1B[0m Test 2 passed\n" +
+      "\x1B[31m✗\x1B[0m Test 3 failed\n" +
+      "Some additional output to make it longer";
+    const result = formatResultContent(longColoredOutput);
+    expect(result).toContain("✓ Test 1 passed");
+    expect(result).toContain("✗ Test 3 failed");
+    expect(result).not.toContain("\x1B");
+  });
 });
 
 describe("formatToolWithResult", () => {

test/sanitizer.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "bun:test";
 import {
+  stripAnsiCodes,
   stripInvisibleCharacters,
   stripMarkdownImageAltText,
   stripMarkdownLinkTitles,
@@ -10,6 +11,51 @@ import {
   redactGitHubTokens,
 } from "../src/github/utils/sanitizer";
 
+describe("stripAnsiCodes", () => {
+  it("should remove color codes", () => {
+    // Bold yellow text: \x1B[1;33m
+    expect(stripAnsiCodes("\x1B[1;33mWarning\x1B[0m")).toBe("Warning");
+    // Red text: \x1B[31m
+    expect(stripAnsiCodes("\x1B[31mError\x1B[0m")).toBe("Error");
+    // Green text: \x1B[32m
+    expect(stripAnsiCodes("\x1B[32mSuccess\x1B[0m")).toBe("Success");
+  });
+
+  it("should remove bold and other style codes", () => {
+    // Bold: \x1B[1m
+    expect(stripAnsiCodes("\x1B[1mBold text\x1B[0m")).toBe("Bold text");
+    // Underline: \x1B[4m
+    expect(stripAnsiCodes("\x1B[4mUnderlined\x1B[0m")).toBe("Underlined");
+  });
+
+  it("should remove cursor movement codes", () => {
+    // Clear line: \x1B[K
+    expect(stripAnsiCodes("Text\x1B[K")).toBe("Text");
+    // Cursor up: \x1B[A
+    expect(stripAnsiCodes("Line1\x1B[ALine2")).toBe("Line1Line2");
+  });
+
+  it("should handle multiple ANSI codes in one string", () => {
+    const input = "\x1B[1;31mError:\x1B[0m \x1B[33mWarning\x1B[0m text";
+    expect(stripAnsiCodes(input)).toBe("Error: Warning text");
+  });
+
+  it("should preserve text without ANSI codes", () => {
+    expect(stripAnsiCodes("Normal text")).toBe("Normal text");
+    expect(stripAnsiCodes("Text with [brackets]")).toBe("Text with [brackets]");
+  });
+
+  it("should handle empty string", () => {
+    expect(stripAnsiCodes("")).toBe("");
+  });
+
+  it("should handle complex terminal output", () => {
+    // Simulates npm/yarn output with colors
+    const input = "\x1B[2K\x1B[1G\x1B[32m✓\x1B[0m Tests passed";
+    expect(stripAnsiCodes(input)).toBe("✓ Tests passed");
+  });
+});
+
 describe("stripInvisibleCharacters", () => {
   it("should remove zero-width characters", () => {
     expect(stripInvisibleCharacters("Hello\u200BWorld")).toBe("HelloWorld");