Imported from Trecek/useful-claude-skills (.claude/skills/id-slop/SKILL.md). Install upstream with npx skills add Trecek/useful-claude-skills --skill id-slop. Copyright stays with the author.

Slop Identification Skill

Identify and catalog AI-generated code slop in the codebase. Slop is useless code patterns left behind by AI assistants during rapid development - comments that won't make sense to future readers, backward compatibility hacks, dead code, and other technical debt.

When to Use

• User says "id slop", "identify slop", "find slop"
• User wants "code cleanup" or "cleanup scan"
• User mentions "AI-generated junk" or "leftover comments"
• User asks to "find useless comments" or "remove dead code"

Critical Constraints

NEVER:

• Modify any source code files (this skill only IDENTIFIES slop)
• Remove code without creating a removal plan first
• Flag legitimate comments, documentation, or architectural patterns
• Flag TODO comments that describe actual future work

ALWAYS:

• Use subagents for parallel exploration
• Write the slop removal plan to temp/id-slop/ directory
• Provide file paths and line numbers for each finding
• Run dry walkthrough on the generated plan
• Categorize slop by type for prioritized removal

Slop Categories

Category 1: Phase Reference Comments (HIGH PRIORITY)

Comments mentioning numbered phases from AI implementation plans that won't make sense to future readers.

Patterns to detect:

• Phase [0-9] in comments or docstrings
• # Phase 1:, # Phase 2:, etc.
• References to "implementation phase" or "migration phase" with numbers
• Part of Phase X comments

Example slop:

# Phase 5: Migrate Checkpoint and Session Management
def migrate_session():  # Part of Phase 2 migration

Category 2: Backward Compatibility Hacks (HIGH PRIORITY)

Parameters or code kept solely for "API compatibility" that's no longer needed.

Patterns to detect:

• kept for API compatibility
• kept for backward compatibility
• unused but kept for
• ignored - kept for
• Parameters that are documented as "unused" or "ignored"

Example slop:

use_file_lock: bool = True,  # Ignored - kept for API compatibility
log_dir: Optional[Path] = None,  # Ignored - kept for API compatibility

Category 3: Removed Code Comments (MEDIUM PRIORITY)

Comments explaining what was removed without explaining what replaced it.

Patterns to detect:

• removed in Phase
• no longer needed
• NOTE: X removed
• References to deleted features or functions

Example slop:

# NOTE: test-and-log removed in Phase 4. Use simple 'test' task.
# baseline_manager removed - now handled by executor

Category 4: Deprecation Notices (MEDIUM PRIORITY)

Comments marking code as deprecated without removal timeline or replacement guidance.

Patterns to detect:

• deprecated without clear migration path
• @deprecated decorators on live code
• will be removed without version/date
• Stale deprecation warnings

Category 5: Fallback/Workaround Code (HIGH PRIORITY)

Fallback logic that masks errors instead of failing fast.

Patterns to detect:

• try: ... except: pass blocks that swallow all exceptions
• # Silently ignore comments
• Fallback methods that don't log the original error
• ignore_errors=True without logging

Example slop:

try:
    result = risky_operation()
except:
    pass  # Silently ignore errors

Category 6: Type System Bypasses (LOW PRIORITY)

Comments that bypass type checking instead of fixing the actual type issue.

Patterns to detect:

• # type: ignore without explanation
• # noqa without specific error code
• cast() calls that don't make type sense

Example slop:

entry.status = status  # type: ignore
return wrapper  # type: ignore

Category 7: Dead Placeholder Code (MEDIUM PRIORITY)

Stub implementations, placeholder nodes, or scaffolding never replaced.

Patterns to detect:

• Functions with only pass or ... bodies
• placeholder or stub in function names
• # TODO: implement without implementation
• Test scaffolding left in production code

Example slop:

def find_next_placeholder(state):
    """Placeholder node for testing."""
    pass

Category 8: Unreachable Code Comments (LOW PRIORITY)

Comments explaining why code is unreachable or can't happen.

Patterns to detect:

• # This should be unreachable
• # Acknowledge unused parameter
• # satisfies mypy for dead code paths
• Defensive code for impossible states

Example slop:

# This should be unreachable if retry_attempts > 0, but satisfies mypy
raise RuntimeError("Unreachable")

Category 9: Commented-Out Code (HIGH PRIORITY)

Code blocks that are commented out instead of deleted.

Patterns to detect:

• Multi-line commented code blocks
• # old_function() style commented calls
• # return old_value commented returns

Category 10: Dead Code (HIGH PRIORITY)

Unused functions, classes, methods, imports, variables, and constants that are never referenced anywhere in the codebase.

Patterns to detect:

• Functions/methods with no callers
• Classes never instantiated or subclassed
• Imports not used in the module
• Variables/constants assigned but never read
• Module-level code that serves no purpose

Investigation Workflow

Step 1: Launch Parallel Subagents

Spawn 4-6 Explore subagents to scan different slop categories simultaneously:

Subagent 1: Phase References & Deprecation
- Search for "Phase [0-9]" patterns in comments
- Search for "deprecated" markers
- Search for "removed in" comments

Subagent 2: Backward Compatibility & Fallbacks
- Search for "kept for" compatibility patterns
- Search for "ignored" parameters
- Search for silent error handling

Subagent 3: Dead Code & Placeholders
- Search for placeholder/stub functions
- Search for unused imports with noqa
- Search for pass-only function bodies

Subagent 4: Type Bypasses & Unreachable Code
- Search for "type: ignore" without explanation
- Search for "noqa" suppressions
- Search for "unreachable" comments

Subagent 5: Commented-Out Code
- Search for multi-line comment blocks that look like code
- Search for commented function calls
- Search for # old_ patterns

Subagent 6: Dead Code
- Search for functions/classes with no callers
- Search for unused imports
- Search for assigned-but-never-read variables

Step 2: Consolidate Findings

After subagents complete, organize findings by:

1. File path
2. Line number(s)
3. Slop category
4. Priority (HIGH/MEDIUM/LOW)
5. Removal action (delete line, delete block, refactor)

Step 3: Generate Removal Plan

Write a structured removal plan to: temp/id-slop/slop_removal_plan_{YYYY-MM-DD_HHMMSS}.md

The plan should follow this format:

# Slop Removal Plan

**Date:** {YYYY-MM-DD}
**Scope:** {directories scanned}
**Total Findings:** {count}

## Summary by Category

| Category | Count | Priority |
|----------|-------|----------|
| Phase References | X | HIGH |
| Backward Compatibility | X | HIGH |
| ... | ... | ... |

## Phase 1: High Priority - Phase Reference Comments

### Objective
Remove all phase reference comments that won't make sense to future readers.

### Files to Modify

- `path/to/file.py:LINE`: Remove comment "# Phase 5: ..."
- `path/to/file.py:LINE-LINE`: Remove docstring section mentioning phases

### Implementation Steps
1. Delete line X in file.py containing "Phase 5" comment
2. Delete lines X-Y in file2.py containing phase docstring
...

### Success Criteria
- [ ] No "Phase [0-9]" patterns remain in comments
- [ ] Code still functions correctly

### Verification
```bash
grep -rn "Phase [0-9]" src/ --include="*.py" | grep -v "test"

Phase 2: High Priority - Backward Compatibility Hacks

Objective

Remove unused parameters kept for backward compatibility.

Files to Modify

...

Phase N: Final Verification

Verification Commands

# Run linting/formatting checks and full test suite

Success Criteria

• All tests pass
• No linting errors
• No functional regressions

### Step 4: Run Dry Walkthrough

After generating the removal plan, invoke the dry walkthrough skill:

Now running dry walkthrough on the slop removal plan...

### Step 5: Report Summary

Output to terminal:

Slop Identification Complete

Plan: temp/id-slop/slop_removal_plan_{YYYY-MM-DD_HHMMSS}.md Total Findings: {count}

By Priority

• HIGH: {count} items (should fix immediately)
• MEDIUM: {count} items (fix when touching these files)
• LOW: {count} items (fix opportunistically)

By Category

1. Phase References: {count}
2. Backward Compatibility: {count}
3. Removed Code Comments: {count}
4. Fallback/Workaround Code: {count}
5. Dead Placeholder Code: {count}
6. Type Bypasses: {count}
7. Dead Code: {count}

Next Steps

1. Review the plan at temp/id-slop/slop_removal_plan_{YYYY-MM-DD_HHMMSS}.md
2. Dry walkthrough has been run - check for any issues
3. Implement the plan phase by phase

## Search Patterns Reference

Use these regex patterns for searching:

```bash
# Phase references
grep -rn "Phase [0-9]" --include="*.py"
grep -rn "# Phase" --include="*.py"

# Backward compatibility
grep -rn "kept for.*compatibility" --include="*.py"
grep -rn "ignored.*kept for" --include="*.py"

# Removed code
grep -rn "removed in Phase" --include="*.py"
grep -rn "no longer needed" --include="*.py"

# Fallbacks
grep -rn "except:.*pass" --include="*.py"
grep -rn "ignore_errors=True" --include="*.py"
grep -rn "Silently ignore" --include="*.py"

# Type bypasses
grep -rn "# type: ignore$" --include="*.py"
grep -rn "# noqa$" --include="*.py"

# Placeholders
grep -rn "placeholder" --include="*.py"
grep -rn "def.*stub" --include="*.py"

# Unreachable
grep -rn "should be unreachable" --include="*.py"
grep -rn "satisfies mypy" --include="*.py"

Exclusions

Do NOT flag as slop:

1. Architecture documentation - Comments explaining design decisions
2. API documentation - Docstrings explaining parameters and return values
3. Legitimate TODOs - TODOs with clear descriptions of future work
4. Test-specific code - Mocks, fixtures, and test utilities
5. Intentional type ignores - Type ignores with explanatory comments
6. Error handling with logging - Exception handlers that log errors
7. Feature flags - Conditional code controlled by configuration