eslint-log-capture

name	eslint-log-capture
description	How to run ESLint and capture its output in a format that's easy for the AI agent to read and process, especially on Windows.

ESLint Log Capture Skill

When dealing with a large number of ESLint warnings or errors, direct terminal output can be truncated, messy, or encoded in a way that's difficult to process. This skill provides a reliable method to capture ESLint output to a file and read it using native tools.

Why this is necessary

On Windows, using > or Out-File in PowerShell often defaults to UTF-16 (little-endian or big-endian depending on version), which can cause issues with the agent's view_file tool or other text processing tools that expect UTF-8.

The Procedure

1. Run ESLint and capture to a raw file

Run the following command to pipe the linting output to a temporary file:

npm run lint -- --format stylish 2>&1 | Out-File -Encoding utf8 lint-raw.log

Note: In PowerShell 5.1, -Encoding utf8 creates a UTF-8 BOM file. In PowerShell Core/7, it's UTF-8 without BOM.

[!TIP] Linting can take several minutes to complete on a large codebase. Use a generous wait duration (e.g. 60 seconds) when checking the command status.

2. (Optional) Convert to pure UTF-8 if needed

If the agent has trouble reading lint-raw.log, convert it using PowerShell to ensure it's standard UTF-8:

Get-Content lint-raw.log | Set-Content -Encoding utf8 lint.log

3. Read and process the results

Once the file is created and confirmed to be in UTF-8, use your environment's file-reading tools (e.g., view_file, cat, or a similar tool) to process the linting results.

Example (using view_file):

{
	"tool": "view_file",
	"arguments": {
		"AbsolutePath": "<ABSOLUTE_PATH_TO_REPO>/lint.log"
	}
}

Best Practices

• Use standard formats: The stylish or json formats are usually best for agent processing.
• Cleanup: Delete the temporary log files (lint-raw.log, lint.log) once the issues are resolved.
• Incremental fixing: If there are many errors, run the lint command on specific directories or files to keep the log manageable.