Audit Defense Standards

Defense Standards Audit Skill

Audit the codebase against defense standards derived from historical bug pattern analysis. Each standard represents an architectural lesson learned from real bugs - a guard that prevents an entire class of bugs, not just one instance.

Standards are added here when /design-guards recommends them and the user approves.

When to Use

• User says "audit defenses", "audit defense standards", "check defenses"
• As a periodic health check to catch regressions
• After major refactors to verify guards still hold

Critical Constraints

NEVER:

• Modify any source code files
• Update an existing report - always generate new

ALWAYS:

• Use subagents for parallel exploration (one per standard or group)
• All output goes under temp/audit-defense-standards/ (create if needed)
• Final report: temp/audit-defense-standards/defense_audit_{YYYY-MM-DD_HHMMSS}.md
• Subagents must NOT create their own files - they return findings in their response text only
• Provide file paths and line numbers for violations
• Categorize by severity

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Defense Standards Template

This skill requires project-specific defense standards. Define them in this section following the format below.

Example Defense Standards

The following examples show common patterns applicable to many codebases. Replace these with project-specific standards derived from your bug pattern analysis.

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DS-1: Typed Boundaries Over Raw Data Access

Rule: Data crossing component boundaries must pass through typed accessors or validation. No raw dict.get() or unvalidated external input at boundary crossings.

Audit Strategy:

• Find raw dict/JSON access on data crossing component boundaries
• Check that boundary-crossing functions use typed parameters, not Dict[str, Any] or unvalidated strings
• Verify no mutation of caller's data (.pop() on function parameters)
• Look for direct external input consumption without schema validation

Severity: HIGH

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DS-2: Error Context Preservation

Rule: When error/failure data passes through transformations or wrappers, the error message/context must be explicitly preserved. Broad exception handlers must not swallow programmer errors.

Audit Strategy:

• Trace error context through transformation chains
• Verify all error factory methods preserve error messages when wrapping
• Find except Exception and except BaseException handlers; verify each is narrowed or justified
• Check that error logs include actionable context (not just "An error occurred")

Severity: HIGH

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DS-3: Validation at Construction Time

Rule: Domain objects must be validated at construction time, not only at persistence boundaries. Direct constructors must not bypass validators.

Audit Strategy:

• Find direct constructor calls for domain models; verify validators fire
• Check that validation happens before business logic operates on the data
• Verify validation errors propagate (not swallowed or logged-only)
• Look for late validation (only at save/persist) that allows invalid state in memory

Severity: HIGH

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Adding Project-Specific Standards

Defense standards come from the /design-guards pipeline:

1. /audit-bugs identifies recurring patterns
2. /design-guards investigates solutions and recommends standards
3. User approves which recommendations become permanent standards
4. Add the approved standards to this file following the format below

Standard format:

### DS-N: {Short Name}

**Rule:** {One-sentence rule statement}

**Audit Strategy:**
{Concrete steps subagents should take to check compliance}

**Severity:** {CRITICAL / HIGH / MEDIUM / LOW}

Before first use: Replace the example standards above with your project's actual defense standards, or keep them as a starting point and add project-specific ones as they're discovered.

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Audit Workflow

1. Launch parallel subagents - one per standard or group of related standards
2. Each subagent: runs the audit strategy, reports violations with file paths and line numbers
3. Consolidate findings by standard and severity
4. Ensure temp/audit-defense-standards/ exists (mkdir -p)
5. Write report to temp/audit-defense-standards/defense_audit_{YYYY-MM-DD_HHMMSS}.md
6. Output summary to terminal: violation count per standard, total by severity

Report Structure

# Defense Standards Audit

**Date:** {today}
**Standards Checked:** {count}

## Summary
| Standard | Violations | Severity |
|----------|-----------|----------|
| DS-1: Typed Boundaries | X | HIGH |
| DS-2: Error Context | X | HIGH |
| ... | ... | ... |

## DS-N: {Standard Name}

### Violations
- {file}:{line} - {description of violation}

### Compliant Patterns Found
{Brief note on good patterns found, if any}

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Severity Guidelines

CRITICAL: Violations that can cause silent data corruption or unrecoverable state HIGH: Violations that cause crashes, validation bypass, or error masking MEDIUM: Violations that cause incorrect behavior in edge cases LOW: Violations that affect code quality but not correctness

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Trecek
• Source: Trecek/useful-claude-skills
• License: MIT

Install and usage instructions live in the source repository linked above.