extract-errors

name	extract-errors
description	Use when extracting, auditing, or standardizing error codes and messages across a codebase. Triggers on "error codes", "error messages", "unknown error", "extract errors", "error registry".
version	1.4.20
compatibility	Claude 4.5+, Sonnet 4.6, Haiku 4.5

Extract & Audit Error Codes

Cross-language skill for finding, cataloguing, and standardizing error codes and messages in any codebase.

When to use

• "unknown error code" warning appears at runtime
• New error messages need codes assigned
• Error messages are inconsistent or duplicated across modules
• Building or auditing an error registry

Instructions

1. Discover all error definitions

# JavaScript / TypeScript
grep -rn "throw new Error\|createError\|ErrorCode\.\|ERROR_" src/ --include="*.ts" --include="*.js"

# Python
grep -rn "raise \|class.*Error\|class.*Exception" . --include="*.py"

# Go
grep -rn "errors.New\|fmt.Errorf\|var Err" . --include="*.go"

# Rust
grep -rn "Err(\|thiserror\|anyhow" . --include="*.rs"

2. Check for unregistered errors

Compare discovered errors against the error registry file (e.g. errors.json, error_codes.py, errors.go). Flag any error string not present in the registry.

3. Assign codes to new errors

• Use sequential numeric codes within the module's range (e.g. AUTH_001–AUTH_099)
• Format: <MODULE>_<NNN> (e.g. GATE_001, HOOK_042)
• Add to the registry with: code, message template, severity (info/warn/error/fatal), owner module

4. Report

Output a table:

Code	Message	Module	Status
GATE_001	Identity verification failed	identity-gate	registered
HOOK_042	Circuit breaker open	token-budget-guard	NEW — needs code

5. Verify

Re-run discovery grep after updating the registry to confirm 0 unregistered errors remain.