dev-team/skills/dev-fuzz-testing/SKILL.md
Gate 4 of development cycle - ensures fuzz tests exist with proper seed corpus to discover edge cases, crashes, and unexpected input handling.
npx skillsauth add lerianstudio/ring ring:dev-fuzz-testingInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Ensure critical parsing and input handling code has fuzz tests to discover crashes and edge cases through random input generation.
Core principle: Fuzz tests find bugs you didn't think to test for. They're mandatory for all code that handles external input.
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This skill ORCHESTRATES. QA Analyst Agent (fuzz mode) EXECUTES.
| Who | Responsibility | |-----|----------------| | This Skill | Gather requirements, dispatch agent, track iterations | | QA Analyst Agent | Write fuzz tests, generate corpus, run fuzz |
MANDATORY: Load testing-fuzz.md standards via WebFetch.
<fetch_required> https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/golang/testing-fuzz.md </fetch_required>
REQUIRED INPUT:
- unit_id: [task/subtask being tested]
- implementation_files: [files from Gate 0]
- language: [go only for native fuzz]
OPTIONAL INPUT:
- gate3_handoff: [full Gate 3 output]
if any REQUIRED input is missing:
→ STOP and report: "Missing required input: [field]"
if language != "go":
→ STOP and report: "Native fuzz testing only supported for Go (Go 1.18+)"
Task tool:
subagent_type: "ring:qa-analyst"
prompt: |
**MODE:** FUZZ TESTING (Gate 4)
**Standards:** Load testing-fuzz.md
**Input:**
- Unit ID: {unit_id}
- Implementation Files: {implementation_files}
- Language: {language}
**Requirements:**
1. Create fuzz functions (FuzzXxx naming)
2. Add seed corpus (minimum 5 entries per function)
3. Run fuzz tests for 30 seconds
4. Report any crashes found
**Output Sections Required:**
- ## Fuzz Testing Summary
- ## Corpus Report
- ## Handoff to Next Gate
Parse agent output:
if "Status: PASS" in output:
→ Gate 4 PASSED
→ Return success with metrics
if "Status: FAIL" in output:
→ Dispatch fix to implementation agent
→ Re-run fuzz tests (max 3 iterations)
→ If still failing: ESCALATE to user
## Fuzz Testing Summary
**Status:** {PASS|FAIL}
**Fuzz Functions:** {count}
**Corpus Entries:** {count}
**Crashes Found:** {count}
## Corpus Report
| Function | Entries | Crashes |
|----------|---------|---------|
| {function_name} | {count} | {count} |
## Handoff to Next Gate
- Ready for Gate 5 (Property Testing): {YES|NO}
- Iterations: {count}
| Severity | Criteria | Examples | |----------|----------|----------| | CRITICAL | Crash found, security vulnerability discovered | Panic on input, buffer overflow, memory corruption | | HIGH | No fuzz functions, missing corpus | Zero FuzzXxx functions, empty seed corpus | | MEDIUM | Insufficient corpus, naming issues | Less than 5 corpus entries, non-standard function names | | LOW | Coverage gaps, optimization | Missing edge case seeds, fuzz duration improvements |
Report all severities. CRITICAL = immediate fix and re-fuzz. HIGH = fix before gate pass. MEDIUM = fix in iteration. LOW = document.
| Rationalization | Why It's WRONG | Required Action | |-----------------|----------------|-----------------| | "Unit tests cover edge cases" | You can't test what you don't think of. Fuzz finds unknowns. | Write fuzz tests | | "Code is too simple for fuzz" | Simple code can still crash on malformed input. | Write fuzz tests | | "Fuzz testing is slow" | 30 seconds per function. Crashes in production are slower. | Write fuzz tests | | "We validate input anyway" | Validation can have bugs too. Fuzz tests the validators. | Write fuzz tests |
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Voice and tone guidelines for technical documentation. Ensures consistent, clear, and human writing across all documentation.