MetaClaw input-validation-and-sanitization

Use this skill when implementing any endpoint, form handler, CLI tool, or function that accepts external input. Validate and sanitize all untrusted data before processing — never assume input is safe.

install

source · Clone the upstream repo

git clone https://github.com/aiming-lab/MetaClaw

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/aiming-lab/MetaClaw "$T" && mkdir -p ~/.claude/skills && cp -r "$T/memory_data/skills/input-validation-and-sanitization" ~/.claude/skills/aiming-lab-metaclaw-input-validation-and-sanitization && rm -rf "$T"

manifest: memory_data/skills/input-validation-and-sanitization/SKILL.md

source content

Input Validation and Sanitization

Validation principles:

Validate at the system boundary (API layer, form handler) — not deep in business logic.
Validate type, range, length, and format explicitly.
Reject unexpected input by default (allowlist > denylist).

SQL injection prevention: Always use parameterized queries or an ORM.

XSS prevention: Escape HTML output; use Content-Security-Policy headers; avoid

innerHTML

with user data.

Path traversal prevention: Resolve paths to canonical form and verify they are under the expected directory.

import os
base = '/allowed/dir'
canonical = os.path.realpath(os.path.join(base, user_input))
assert canonical.startswith(base + os.sep)