name: failure-mode-analysis
description: "Apply MECE failure mode taxonomy to backend pipelines. Classifies failures by Location (L1-L4), Type (T1-T5), and Severity (S1-S4). Produces comprehensive failure mode inventory with validation status and coverage calculation."
phase: REVIEW
category: core
version: "1.0.0"
depends_on: [pipeline-discovery]
tags: [audit, failure-modes, mece, backend, analysis]

Failure Mode Analysis

Apply MECE failure mode taxonomy to backend pipelines.

When to Use

• After pipeline discovery — Runs in REVIEW phase on identified P-series
• Systematic failure identification — Find all ways each pipeline can fail
• Coverage assessment — Calculate what percentage of failures are validated
• When you say: "analyze failure modes", "what can break?", "find the risks"

Reference Requirements

MUST read before applying this skill:

Read if applicable:

Verification: Every pipeline step has been analyzed for failure modes.

Required Deliverables

Core Concept

Failure Mode Analysis answers: "What are all the ways this pipeline can fail?"

MECE = Mutually Exclusive, Collectively Exhaustive
- Every failure belongs to exactly one category
- All possible failures are covered

The three dimensions:
1. Location (WHERE) — Where in the pipeline does it fail?
2. Type (WHAT) — What kind of failure is it?
3. Severity (HOW BAD) — How serious is the impact?

The MECE Taxonomy

Dimension 1: Location (WHERE)

Dimension 2: Type (WHAT)

Dimension 3: Severity (HOW BAD)

Analysis Process

┌─────────────────────────────────────────────────────────────┐
│              FAILURE MODE ANALYSIS PROCESS                  │
│                                                             │
│  FOR EACH PIPELINE:                                         │
│                                                             │
│  1. WALK THROUGH EACH STEP                                  │
│     └─→ What can go wrong at this step?                    │
│                                                             │
│  2. FOR EACH POTENTIAL FAILURE                              │
│     ├─→ Assign Location (L1-L4)                            │
│     ├─→ Assign Type (T1-T5)                                │
│     ├─→ Assign Severity (S1-S4)                            │
│     └─→ Generate ID: P{N}-{NNN}                            │
│                                                             │
│  3. CHECK VALIDATION STATUS                                 │
│     ├─→ Is there explicit error handling?                  │
│     ├─→ Is there test coverage?                            │
│     └─→ Mark VALIDATED or UNVALIDATED                      │
│                                                             │
│  4. CALCULATE COVERAGE                                      │
│     └─→ (Validated / Total) × 100%                         │
└─────────────────────────────────────────────────────────────┘

Failure Mode Documentation

### P2-007: Template selection too narrow

| Attribute | Value |
|-----------|-------|
| **ID** | P2-007 |
| **Pipeline** | P2: Content Generation |
| **Step** | 4. Template selection |
| **Location** | L2-Processing |
| **Type** | T4-Quality |
| **Severity** | S1-Silent |
| **Description** | Only 3 templates available, causing repetitive output |
| **Impact** | Generated content lacks variety |
| **Detection** | None (silent) |
| **Status** | UNVALIDATED |
| **Test Spec** | TEST-P2-007 |
| **Fix** | Expand template pool to 10+ variations |
| **Effort** | M |

Output Format

PIPELINE-FAILURE-MODES.md

# Pipeline Failure Modes

## Summary

| Pipeline | Failure Modes | Validated | Coverage |
|----------|---------------|-----------|----------|
| P1: Source Ingestion | 9 | 4 | 44% |
| P2: Content Generation | 12 | 3 | 25% |
| P3: Publishing | 8 | 5 | 63% |
| **Total** | **29** | **12** | **41%** |

## Risk Distribution

| Severity | Count | Validated | Risk Level |
|----------|-------|-----------|------------|
| S1-Silent | 8 | 2 | HIGHEST |
| S2-Partial | 7 | 3 | HIGH |
| S3-Visible | 9 | 5 | MEDIUM |
| S4-Blocking | 5 | 2 | LOW |

## P1: Source Ingestion

### P1-001: File type not supported

| Attribute | Value |
|-----------|-------|
| **Location** | L1-Input |
| **Type** | T1-Data |
| **Severity** | S3-Visible |
| **Description** | User uploads unsupported file type |
| **Status** | VALIDATED (try-catch in upload handler) |

[... more failure modes ...]

Coverage Calculation

A failure mode is Validated only if:

1. Explicit handling exists:
   typescript try { await processFile(file); } catch (error) { // Specific handling for this failure }

2. Test coverage exists:
   typescript test('handles unsupported file type', () => { expect(() => upload(badFile)).toThrow(); });

Coverage formula:

Coverage = (Validated Modes / Total Modes) × 100%

Priority Order for Fixes

1. S1 (Silent) — Highest risk: fail without anyone knowing
2. L4 (Integration) — High risk: cross-pipeline, often 0% validated
3. S2 (Partial) — Medium risk: data corruption possible
4. S3 (Visible) — Lower risk: at least user knows
5. S4 (Blocking) — Usually already handled (obvious failures)

Validation Checklist

• [ ] Every pipeline step analyzed
• [ ] Each failure mode has L/T/S codes
• [ ] Unique ID assigned (P{N}-{NNN})
• [ ] Validation status checked against code
• [ ] Coverage percentages calculated
• [ ] Summary table generated