Focused Fix — Deep-Dive Feature Repair

When to Use

Activate when the user asks to fix, debug, or make a specific feature/module/area work. Key triggers:

• "make X work"
• "fix the Y feature"
• "the Z module is broken"
• "focus on area]"
• "this feature needs to work properly"

This is NOT for quick single-bug fixes (use systematic-debugging for that). This is for when an entire feature or module needs systematic repair — tracing every dependency, reading logs, checking tests, mapping the full dependency graph.

dot
digraph when_to_use {
    "User reports feature broken" [shape=diamond];
    "Single bug or symptom?" [shape=diamond];
    "Use systematic-debugging" [shape=box];
    "Entire feature/module needs repair?" [shape=diamond];
    "Use focused-fix" [shape=box];
    "Something else" [shape=box];

    "User reports feature broken" -> "Single bug or symptom?";
    "Single bug or symptom?" -> "Use systematic-debugging" [label="yes"];
    "Single bug or symptom?" -> "Entire feature/module needs repair?" [label="no"];
    "Entire feature/module needs repair?" -> "Use focused-fix" [label="yes"];
    "Entire feature/module needs repair?" -> "Something else" [label="no"];
}

The Iron Law

NO FIXES WITHOUT COMPLETING SCOPE → TRACE → DIAGNOSE FIRST

If you haven't finished Phase 3, you cannot propose fixes. Period.

Violating the letter of these phases is violating the spirit of focused repair.

Protocol — STRICTLY follow these 5 phases IN ORDER

dot
digraph phases {
    rankdir=LR;
    SCOPE [shape=box, label="Phase 1\nSCOPE"];
    TRACE [shape=box, label="Phase 2\nTRACE"];
    DIAGNOSE [shape=box, label="Phase 3\nDIAGNOSE"];
    FIX [shape=box, label="Phase 4\nFIX"];
    VERIFY [shape=box, label="Phase 5\nVERIFY"];

    SCOPE -> TRACE -> DIAGNOSE -> FIX -> VERIFY;
    FIX -> DIAGNOSE [label="fix broke\nsomething else"];
    FIX -> ESCALATE [label="3+ fixes\ncreate new issues"];
    ESCALATE [shape=doubleoctagon, label="STOP\nQuestion Architecture\nDiscuss with User"];
}

Phase 1: SCOPE — Map the Feature Boundary

Before touching any code, understand the full scope of the feature.

1. Ask the user: "Which feature/folder should I focus on?" if not already clear
2. Identify the PRIMARY folder/files for this feature
3. Map EVERY file in that folder — read each one, understand its purpose
4. Create a feature manifest:

FEATURE SCOPE:
  Primary path: src/features/auth/
  Entry points: [files that are imported by other parts of the app]
  Internal files: [files only used within this feature]
  Total files: N
  Total lines: N

Phase 2: TRACE — Map All Dependencies (Inside AND Outside)

Trace every connection this feature has to the rest of the codebase.

INBOUND (what this feature imports):

1. For every import statement in every file in the feature folder:

• Trace it to its source
• Verify the source file exists
• Verify the imported entity (function, type, component) exists and is exported
• Check if the types/signatures match what the feature expects

1. Check for:

• Environment variables used (grep for process.env, import.meta.env, os.environ, etc.)
• Config files referenced
• Database models/schemas used
• API endpoints called
• Third-party packages imported

OUTBOUND (what imports this feature):

1. Search the entire codebase for imports from this feature folder
2. For each consumer:

• Verify they're importing entities that actually exist
• Check if they're using the correct API/interface
• Note if any consumers are using deprecated patterns

Output format:

DEPENDENCY MAP:
  Inbound (this feature depends on):
    src/lib/db.ts → used in auth/repository.ts (getUserById, createUser)
    src/lib/jwt.ts → used in auth/service.ts (signToken, verifyToken)
    @prisma/client → used in auth/repository.ts
    process.env.JWT_SECRET → used in auth/service.ts
    process.env.DATABASE_URL → used via prisma

  Outbound (depends on this feature):
    src/app/api/login/route.ts → imports { login } from auth/service
    src/app/api/register/route.ts → imports { register } from auth/service
    src/middleware.ts → imports { verifyToken } from auth/service

  Env vars required: JWT_SECRET, DATABASE_URL
  Config files: prisma/schema.prisma (User model)

Phase 3: DIAGNOSE — Find Every Issue

Systematically check for problems. Run ALL of these checks:

CODE QUALITY:

• ] Every import resolves to a real file/export
• ] No circular dependencies within the feature
• ] Types are consistent across boundaries (no any at interfaces)
• ] Error handling exists for all async operations
• ] No TODO/FIXME/HACK comments indicating known issues

RUNTIME:

• ] All required environment variables are set (check .env)
• ] Database migrations are up to date (if applicable)
• ] API endpoints return expected shapes
• ] No hardcoded values that should be configurable

TESTS:

• ] Run ALL tests related to this feature: find them by searching for imports from the feature folder
• ] Record every failure with full error output
• ] Check test coverage — are there untested code paths?

LOGS & ERRORS:

• ] Search for any log files, error reports, or Sentry-style error tracking
• ] Check git log for recent changes to this feature: git log --oneline -20 -- <feature-path>
• ] Check if any recent commits might have broken something: git log --oneline -5 --all -- <files that this feature depends on>

CONFIGURATION:

• ] Verify all config files this feature depends on are valid
• ] Check for mismatches between development and production configs
• ] Verify third-party service credentials are valid (if testable)

ROOT-CAUSE CONFIRMATION: For each CRITICAL issue found, confirm root cause before adding it to the fix list:

• State clearly: "I think X is the root cause because Y"
• Trace the data/control flow backward to verify — don't trust surface-level symptoms
• If the issue spans multiple components, add diagnostic logging at each boundary to identify which layer fails
• REQUIRED SUB-SKILL: For complex bugs found during diagnosis, apply superpowers:systematic-debugging Phase 1 (Root Cause Investigation) to confirm before proceeding

RISK LABELING: Assign each issue a risk label:

| Risk | Criteria | |---|---| | HIGH | Public API surface / breaking interface contract / DB schema / auth or security logic / widely imported module (>3 callers) / git hotspot | | MED | Internal module with tests / shared utility / config with runtime impact / internal callers of changed functions | | LOW | Leaf module / isolated file / test-only change / single-purpose helper with no callers |

Output format:

DIAGNOSIS REPORT:
  Issues found: N

  CRITICAL:
    1. [HIGH] [file:line] — description of issue. Root cause: [confirmed explanation]
    2. [HIGH] [file:line] — description of issue. Root cause: [confirmed explanation]

  WARNINGS:
    1. [MED] [file:line] — description of issue
    2. [LOW] [file:line] — description of issue

  TESTS:
    Ran: N tests
    Passed: N
    Failed: N
    [list each failure with one-line summary]

Phase 4: FIX — Repair Everything Systematically

Fix issues in this EXACT order:

1. DEPENDENCIES FIRST — fix broken imports, missing packages, wrong versions
2. TYPES SECOND — fix type mismatches at feature boundaries
3. LOGIC THIRD — fix actual business logic bugs
4. TESTS FOURTH — fix or create tests for each fix
5. INTEGRATION LAST — verify the feature works end-to-end with its consumers

Rules:

• Fix ONE issue at a time
• After each fix, run the related test to confirm it works
• If a fix breaks something else, STOP and re-evaluate (go back to DIAGNOSE)
• Keep a running log of every change made
• Never change code outside the feature folder without explicitly stating why
• Fix HIGH-risk issues before MED, MED before LOW

ESCALATION RULE — 3-Strike Architecture Check: If 3+ fixes in this phase create NEW issues (not pre-existing ones), STOP immediately.

This pattern indicates an architectural problem, not a bug collection:

• Each fix reveals new shared state / coupling / problem in a different place
• Fixes require "massive refactoring" to implement
• Each fix creates new symptoms elsewhere

Action: Stop fixing. Tell the user: "3+ fixes have cascaded into new issues. This suggests the feature's architecture may need rethinking, not patching. Here's what I've found: summary]. Should we continue fixing symptoms or discuss restructuring?"

Do NOT attempt fix #4 without this discussion.

Output after each fix:

FIX #1:
  File: auth/service.ts:45
  Issue: signToken called with wrong argument order
  Change: swapped (expiresIn, payload) to (payload, expiresIn)
  Test: auth.test.ts → PASSES

Phase 5: VERIFY — Confirm Everything Works

After all fixes are applied:

1. Run ALL tests in the feature folder — every single one must pass
2. Run ALL tests in files that IMPORT from this feature — must pass
3. Run the full test suite if available — check for regressions
4. If the feature has a UI, describe how to manually verify it
5. Summarize all changes made

Final output:

FOCUSED FIX COMPLETE:
  Feature: auth
  Files changed: 4
  Total fixes: 7
  Tests: 23/23 passing
  Regressions: 0

  Changes:
    1. auth/service.ts — fixed token signing argument order
    2. auth/repository.ts — added null check for user lookup
    3. auth/middleware.ts — fixed async error handling
    4. auth/types.ts — aligned UserResponse type with actual DB schema

  Consumers verified:
    - src/app/api/login/route.ts ✅
    - src/app/api/register/route.ts ✅
    - src/middleware.ts ✅

Red Flags — STOP and Return to Current Phase

If you catch yourself thinking any of these, you are skipping phases:

• "I can see the bug, let me just fix it" → STOP. You haven't traced dependencies yet.
• "Scoping is overkill, it's obviously just this file" → STOP. That's always wrong for feature-level fixes.
• "I'll map dependencies after I fix the obvious stuff" → STOP. You'll miss root causes.
• "The user said fix X, so I only need to look at X" → STOP. Features have dependencies.
• "Tests are passing so I'm done" → STOP. Did you run consumer tests too?
• "I don't need to check env vars for this" → STOP. Config issues masquerade as code bugs.
• "One more fix should do it" (after 2+ cascading failures) → STOP. Escalate.
• "I'll skip the diagnosis report, the fixes are obvious" → STOP. Write it down.

ALL of these mean: Return to the phase you're supposed to be in.

Common Rationalizations

| Excuse | Reality | |---|---| | "The feature is small, I don't need all 5 phases" | Small features have dependencies too. Phases 1-2 take minutes for small features — do them. | | "I already know this codebase" | Knowledge decays. Trace the actual imports, don't rely on memory. | | "The user wants speed, not process" | Skipping phases causes rework. Systematic is faster than thrashing. | | "Only one file is broken" | If only one file were broken, the user would say "fix this bug", not "make the feature work." | | "I fixed the tests, so it works" | Tests can pass while consumers are broken. Verify Phase 5 fully. | | "The dependency map is too big to trace" | Then the feature is too big to fix without tracing. That's exactly why you need it. | | "Root cause is obvious, I don't need to confirm" | "Obvious" root causes are wrong 40% of the time. Confirm with evidence. | | "3 cascading failures is normal for a big fix" | 3 cascading failures means you're patching symptoms of an architectural problem. |

Anti-Patterns — NEVER do these

| Anti-Pattern | Why It's Wrong | |---|---| | Starting to fix code before mapping all dependencies | You'll miss root causes and create whack-a-mole fixes | | Fixing only the file the user mentioned | Related files likely have issues too | | Ignoring environment variables and configuration | Many "code bugs" are actually config issues | | Skipping the test run phase | You can't verify fixes without running tests | | Making changes outside the feature folder without explaining why | Unexpected side effects confuse the user | | Fixing symptoms in consumer files instead of root cause in feature | Band-aids that break when the next consumer appears | | Declaring "done" without running verification tests | Untested fixes are unverified fixes | | Changing the public API without updating all consumers | Breaks everything that depends on the feature |

Related Skills

• superpowers:systematic-debugging — Use within Phase 3 for root-cause tracing of individual complex bugs
• superpowers:verification-before-completion — Use within Phase 5 before claiming the feature is fixed
• scope — If you need to understand blast radius before starting, run scope first then focused-fix

Quick Reference

| Phase | Key Action | Output | |---|---|---| | SCOPE | Read every file, map entry points | Feature manifest | | TRACE | Map inbound + outbound dependencies | Dependency map | | DIAGNOSE | Check code, runtime, tests, logs, config | Diagnosis report | | FIX | Fix in order: deps → types → logic → tests → integration | Fix log per issue | | VERIFY | Run all tests, check consumers, summarize | Completion report |