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.

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

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
2. 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