Design Spec Auditor

Verify that code implementations match their design specifications and identify inconsistencies.

Current State

• Planned design docs: !'ls design_docs/planned/ 2>/dev/null | head -10'
• Implemented design docs: !'ls design_docs/implemented/ 2>/dev/null | tail -5'
• Branch: !'git branch --show-current'
• Recent changes: !'git log --oneline -5'

Use the data above first. Only re-run these commands manually if the injected context is empty or you need to refresh after making changes.

Quick Start

Most common usage:

# User says: "Check if parser matches the design doc"
# This skill will:
# 1. Read design doc (design_docs/planned/ or implemented/)
# 2. Read corresponding code
# 3. Compare and identify discrepancies
# 4. Generate compliance report

When to Use This Skill

Invoke when user says:

• "Check if implementation matches design"
• "Audit the parser against its spec"
• "Verify code compliance"
• "Review design alignment"

Also use:

• After implementing new features
• During code reviews
• After refactoring

Workflow

Step 1: Identify Design Documents

# Find relevant design docs
ls design_docs/planned/     # Planned features
ls design_docs/implemented/ # Completed features

# For a specific feature:
find design_docs -name "*parser*" -o -name "*type*"

Step 2: Map Design to Code

For each design component, identify:

Step 3: Systematic Comparison

Check each design requirement:

1. Architectural decisions

- Are module boundaries respected? - Are dependencies one-way as specified?

1. Interface contracts

- Do function signatures match spec? - Are return types correct?

1. Behavioral requirements

- Does error handling match spec? - Are edge cases covered?

1. Performance requirements

- Are complexity bounds met? - Are resource limits respected?

Step 4: Categorize Discrepancies

Step 5: Generate Report

Report format:

# Design Compliance Audit: [Feature Name]

## Summary
- **Compliance**: 85%
- **Critical Issues**: 0
- **Major Issues**: 2
- **Minor Issues**: 5

## Critical Issues
(none)

## Major Issues

### Issue 1: Missing error propagation
- **Design doc**: design_docs/implemented/v0_3_0/effects.md, Section 3.2
- **Code location**: internal/effects/handler.go:145-160
- **Discrepancy**: Design specifies errors should propagate to caller; code silently ignores
- **Recommendation**: Fix code to match design

## Minor Issues
...

## Recommendations
1. Update internal/effects/handler.go to propagate errors
2. Add missing test cases for edge conditions
3. Update design doc section 4.1 to reflect actual behavior

Comparison Checklist

Use this checklist for each audit:

• Module structure matches design
• Public APIs match signatures in spec
• Error types and handling match spec
• Data structures match definitions
• Invariants are enforced
• Performance requirements met
• Tests cover specified scenarios
• Edge cases handled as specified

Common Discrepancy Patterns

Intentional Deviations

Sometimes code legitimately differs from design:

• Performance optimizations
• Discovered constraints during implementation
• Pragmatic simplifications

Action: Update design doc to reflect reality

Unintentional Oversights

• Forgot to implement a feature
• Misunderstood requirement
• Copy-paste errors

Action: Fix code to match design

Design Drift

Design docs lag behind rapid development:

• Features added without updating docs
• Refactoring changed structure

Action: Update design docs

Example Session

User: "Check if the type system matches its design"

Response:

Auditing type system against design_docs/implemented/v0_3_0/type-system.md...

Reading design doc... Found 15 specified behaviors
Reading code in internal/types/... Found 12 implemented

## Compliance Report: Type System

### Summary
- Compliance: 80%
- Critical: 0
- Major: 1
- Minor: 2

### Major Issues

1. **Row polymorphism extension**
   - Design: Section 4.2 specifies record extension syntax `{...r, x: T}`
   - Code: internal/types/unify.go only supports field access, not extension
   - Action: Implement extension or mark as "planned" in docs

### Minor Issues

1. **Naming**: Design uses "type variable", code uses "tyvar"
2. **Extra**: Code has `TypeCache` not mentioned in design

### Recommendations
1. Implement row extension or update roadmap
2. Add TypeCache to design doc (performance optimization)

Auditing Agent-Executed Work

When auditing sprint executor or other agent work against design specs, also verify the agent's conversation history to detect skipped tasks:

# View agent reasoning per turn (grouped text + tool calls)
ailang coordinator logs <task-id> --limit 1000 --json | python3 -c "
import json, sys
data = json.load(sys.stdin)
events = data.get('events', [])
turns = {}; tools = {}
for evt in events:
    tn = evt.get('turn_num', 0); st = evt.get('stream_type', '')
    if st == 'text': turns.setdefault(tn, []).append(evt.get('text', ''))
    elif st == 'tool_use': tools.setdefault(tn, []).append(evt.get('tool_name', '?'))
for tn in sorted(turns.keys()):
    text = ''.join(turns[tn]).strip()
    if len(text) > 20:
        print(f'=== Turn {tn} (tools: {\", \".join(tools.get(tn, []))}) ===')
        print(text[:600]); print()
"

# View chain execution flow (recommended)
ailang chains view <chain-id> --spans
ailang chains tree <chain-id> --detailed

# View tool usage timeline (requires server)
ailang dashboard spans --task-id <task-id> --limit 200

# View git changes made by agent
ailang coordinator diff <task-id>

Cross-reference checklist:

• Sprint plan acceptance criteria vs actual git diff
• Did agent modify internal/ code or just create examples/docs?
• What model was used? (Check executor.model in spans - Haiku may be too weak for compiler tasks)
• Did it run ailang run (runtime test) or just ailang check (compile test)?
• Did it mark tasks as "already working" without verifying the specific bug scenario?

Tips

• Newer docs supersede older ones - check dates
• Some deviations are intentional - document them
• Focus on behavior, not exact wording
• Consider evolution - designs change over time