What causes "Pattern "${pattern}" escapes the base directory" in n8n-io/n8n?

Use relative patterns only (e.g. 'src/**/*.ts', '**/*.json')

n8n-io/n8n · warning · Error

Pattern "${pattern}" escapes the base directory

Error message

Pattern "${pattern}" escapes the base directory

What it means

Thrown by assertPatternStaysInside() (called from the search_files tool) when a glob pattern starts with '/' (absolute path) or contains '..' as a segment. This prevents the search tool from escaping the base directory via the pattern itself, complementing the per-file path resolution guard.

Source

Thrown at packages/@n8n/computer-use/src/tools/filesystem/search-files.ts:114

		return formatCallToolResult({
			name,
			query,
			matches: matches.slice(0, limit),
			truncated: matches.length > limit,
			totalMatches: matches.length,
		});
	},
};

interface ResolvedFile {
	path: string;
	absolutePath: string;
}

function assertPatternStaysInside(pattern: string): void {
	if (pattern.startsWith('/') || pattern.split('/').includes('..')) {
		throw new Error(`Pattern "${pattern}" escapes the base directory`);
	}
}

async function grepFile(
	file: ResolvedFile,
	regex: RegExp,
): Promise<Array<{ path: string; lineNumber: number; line: string }>> {
	try {
		const stat = await fs.stat(file.absolutePath);
		if (stat.size > MAX_FILE_SIZE) return [];

		const buffer = await fs.readFile(file.absolutePath);
		if (isLikelyBinaryContent(buffer)) return [];

		const lines = buffer.toString('utf-8').split('\n');
		const hits: Array<{ path: string; lineNumber: number; line: string }> = [];
		for (let i = 0; i < lines.length; i++) {
			if (regex.test(lines[i])) {

View on GitHub (pinned to 5ac6606e81)

Solutions

Use relative patterns only (e.g. 'src/**/*.ts', '**/*.json')
Remove any leading '/' from the pattern
Remove all '..' segments from the pattern

Example fix

// before (pattern escapes base directory):
await search_files({ pattern: 'ERROR', glob: '../syslog/**' });

// after (use a relative pattern within the base directory):
await search_files({ pattern: 'ERROR', glob: 'logs/**/*.log' });

Defensive patterns

Strategy: validation

Validate before calling

function isPatternSafe(pattern: string): boolean {
  return !pattern.startsWith('/') && !pattern.split('/').includes('..');
}

// Before calling search_files:
if (!isPatternSafe(globPattern)) {
  throw new Error(`Pattern "${globPattern}" must be relative and not contain '..'`);
}

Type guard

function isPatternEscapeError(e: unknown): boolean {
  return e instanceof Error && e.message.startsWith('Pattern "') && e.message.includes('escapes the base directory');
}

Prevention

Use relative glob patterns only (e.g. 'src/**/*.ts')
Never use leading '/' or '..' segments in search patterns
Validate patterns with a simple check before passing them to search_files

When it happens

Trigger: A search_files call with a pattern like '/etc/**' (absolute), '../secrets/**' (traversal), or 'src/../../outside/**'. The check splits on '/' and looks for '..' segments, and checks for a leading '/'.

Common situations: Agent constructs a search pattern with an absolute path or with '..' traversal segments, or copies a file path verbatim into the pattern field.

Related errors

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/d728e0dc764dacde. Report an issue: GitHub.