scaffold

name	scaffold
description	[Architecture] Use when scaffolding reusable OOP/SOLID project foundations before feature implementation.

Codex compatibility note:

• Invoke repository skills with $skill-name in Codex; this mirrored copy rewrites legacy Claude /skill-name references.
• Prefer the plan-hard skill for planning guidance in this Codex mirror.
• Task tracker mandate: BEFORE executing any workflow or skill step, create/update task tracking for all steps and keep it synchronized as progress changes.
• User-question prompts mean to ask the user directly in Codex.
• Ignore Claude-specific mode-switch instructions when they appear.
• Strict execution contract: when a user explicitly invokes a skill, execute that skill protocol as written.
• Subagent authorization: when a skill is user-invoked or AI-detected and its protocol requires subagents, that skill activation authorizes use of the required spawn_agent subagent(s) for that task.
• Do not skip, reorder, or merge protocol steps unless the user explicitly approves the deviation first.
• For workflow skills, execute each listed child-skill step explicitly and report step-by-step evidence.
• If a required step/tool cannot run in this environment, stop and ask the user before adapting.

Codex Project-Reference Loading (No Hooks)

Codex does not receive Claude hook-based doc injection. When coding, planning, debugging, testing, or reviewing, open project docs explicitly using this routing.

Always read:

• docs/project-config.json (project-specific paths, commands, modules, and workflow/test settings)
• docs/project-reference/docs-index-reference.md (routes to the full docs/project-reference/* catalog)
• docs/project-reference/lessons.md (always-on guardrails and anti-patterns)

Situation-based docs:

• Backend/CQRS/API/domain/entity changes: backend-patterns-reference.md, domain-entities-reference.md, project-structure-reference.md
• Frontend/UI/styling/design-system: frontend-patterns-reference.md, scss-styling-guide.md, design-system/README.md
• Spec/test-case planning or TC mapping: feature-docs-reference.md
• Integration test implementation/review: integration-test-reference.md
• E2E test implementation/review: e2e-test-reference.md
• Code review/audit work: code-review-rules.md plus domain docs above based on changed files

Do not read all docs blindly. Start from docs-index-reference.md, then open only relevant files for the task.

[BLOCKING] Execute skill steps in declared order. NEVER skip, reorder, or merge steps without explicit user approval. [BLOCKING] Before each step or sub-skill call, update task tracking: set in_progress when step starts, set completed when step ends. [BLOCKING] Every completed/skipped step MUST include brief evidence or explicit skip reason. [BLOCKING] If Task tools are unavailable, create and maintain an equivalent step-by-step plan tracker with the same status transitions.

Quick Summary

Goal: Generate and validate the project's architecture scaffolding — all base classes, interfaces, infrastructure abstractions, and reusable foundation code — BEFORE any feature story implementation begins.

Purpose: The scaffolded project should be copy-ready as a starter template for similar projects. All base code, utilities, interfaces, and infrastructure services are created. All setup follows best practices with generic functions any feature story could reuse.

Key distinction: This is architecture infrastructure creation, NOT feature implementation. Creates the foundation layer that all stories build upon.

Be skeptical. Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence percentages (Idea should be more than 80%).

Activation Guards (MANDATORY — Check Before Executing)

ALL conditions must be true to proceed:

1. Workflow check: Active workflow is greenfield-init OR big-feature. If not → SKIP this skill entirely, mark step as completed.
2. Existing scaffolding check: AI MUST ATTENTION self-investigate for existing base/foundational abstractions:
   • Abstract/base classes: grep abstract class.*Base|Base[A-Z]\w+|Abstract[A-Z]\w+
   • Generic interfaces: grep interface I\w+<|IGeneric|IBase
   • Infrastructure abstractions: grep IRepository|IUnitOfWork|IService|IHandler
   • Utility/extension layers: grep Extensions|Helpers|Utils|Common (directories or classes)
   • Frontend foundations: grep base.*component|base.*service|base.*store|abstract.*component (case-insensitive)
   • DI/IoC registration: grep AddScoped|AddSingleton|providers:|NgModule|@Injectable
3. If existing scaffolding found → SKIP. Log: "Existing scaffolding detected at {file:line}. Skipping $scaffold step." Mark step as completed.
4. If NO foundational abstractions found → PROCEED with full scaffolding workflow below.

When to Use

• After the second $plan-hard + $plan-review in greenfield-init or big-feature workflows
• Before $cook begins implementing feature stories
• When a new service/module needs its own base architecture within an existing project
• NOT when the project already has established base classes and infrastructure

Workflow

1. Read Plan — Parse the implementation plan for architecture decisions, tech stack, and domain model
2. Generate Scaffolding Checklist — Produce a checklist of all required base classes and infrastructure from the Backend + Frontend checklists below
3. Validate Against Plan — Ensure every architecture decision in the plan has corresponding scaffolding items
4. Present to User — Use a direct user question to confirm checklist before generating code
5. Scaffold — Create all base classes, interfaces, abstractions, and infrastructure code
6. Verify — Compile/build to ensure no syntax errors; validate OOP/SOLID compliance

Backend Scaffolding Categories

AI must self-investigate the chosen tech stack and produce a checklist covering these categories. Names below are illustrative — adapt to match the project's language, framework conventions, and actual needs.

Domain Layer

• Base entity interface + abstract class (Id, timestamps, audit fields)
• Value object base (equality by value)
• Domain event interface

Application Layer

• Command/query handler abstractions (CQRS if applicable)
• Validation result pattern
• Base DTO with mapping protocol
• Pagination wrapper
• Operation result pattern (success/failure)

Infrastructure Layer

• Generic repository interface + one concrete implementation
• Unit of work interface (if applicable)
• Messaging/event bus abstraction
• External service abstractions (cache, storage, email — only if plan requires them)
• Database context / connection setup
• DI/IoC registration module

Cross-Cutting

• Current user context abstraction
• Testable date/time provider
• Exception hierarchy (domain, validation, not-found)
• Error handling middleware
• Strongly-typed configuration models

Frontend Scaffolding Categories

Core Architecture

• Base component with lifecycle/destroy cleanup
• Base form component with validation, dirty tracking
• Base list component with pagination, sorting, filtering

State & API

• Base state store with loading/error/data pattern
• Base API service with interceptors, error handling
• Auth interceptor + environment config

Shared Utilities

• Base model with serialization helpers
• Common utility functions (date, validation, formatting)

UI Foundation

Skip if: Backend-only project, no frontend component. Apply if: Project has ANY frontend.

Design Token Files

• Create design token file(s) per chosen format (CSS custom properties / SCSS variables / JSON)
• Define minimum token set: colors (primary, secondary, surface, bg, text, error, success, warning), spacing (xs-xl), typography (heading/body/caption families + sizes), breakpoints, shadows, z-index
• Create theme file(s) if theming required (light/dark CSS classes or theme provider)

Base Layout & Responsive

• Base layout component (app shell: header, sidebar/nav, main content, footer)
• Responsive container/grid utility
• Responsive mixin/utility for breakpoints
• Mobile-first media query definitions

Base UI Components

• Loading indicator component (spinner or skeleton)
• Error display component (inline + page-level)
• Empty state component (message + action)
• Notification/toast component
• Base button component with variants (primary, secondary, ghost, danger)
• Base input component with validation display

Design System Documentation

• Create docs/project-reference/design-system/README.md skeleton with: token naming conventions, component tier classification (Common/Domain-Shared/Page), usage examples (read directly when relevant; do not rely on hook-injected conversation text)

Code Quality Gate Tooling (MANDATORY MUST ATTENTION — Setup Before Any Feature Code)

MANDATORY IMPORTANT MUST ATTENTION scaffold ALL code quality enforcement tools as part of project infrastructure — code that passes without quality gates is technical debt from day one.

Static Analysis & Linting

• MANDATORY MUST ATTENTION configure language-appropriate linter with strict ruleset (zero warnings policy on new code)
• MANDATORY MUST ATTENTION configure static code analyzer with quality gate thresholds (complexity, duplication, coverage)
• MANDATORY MUST ATTENTION enable compiler/transpiler strict mode and treat warnings as errors on build
• MANDATORY MUST ATTENTION add code style formatter with shared config (enforce consistent formatting across team)

Build-Time Quality Enforcement

• MANDATORY MUST ATTENTION configure pre-commit hooks to run linter + formatter automatically
• MANDATORY MUST ATTENTION configure CI pipeline to fail on any linter violation, analyzer warning, or test failure
• MANDATORY MUST ATTENTION set minimum test coverage threshold in CI (fail build if below)
• MANDATORY MUST ATTENTION enable security vulnerability scanning in dependency management

Code Rules & Standards

• MANDATORY MUST ATTENTION create shared linter config file at project root (team-wide consistency)
• MANDATORY MUST ATTENTION create shared formatter config file at project root
• MANDATORY MUST ATTENTION create .editorconfig for cross-IDE consistency (indentation, encoding, line endings)
• MANDATORY MUST ATTENTION document code quality standards in project README or contributing guide

Harness Integration (MANDATORY — Do Not Skip)

MANDATORY MUST ATTENTION delegate ALL computational sensor setup to $linter-setup:

• Do NOT manually configure linters, formatters, or pre-commit hooks in this skill
• $linter-setup handles: tool research → install → configure → pre-commit hooks → CI gates
• $harness-setup handles: full harness inventory (feedforward guides + all feedback types)

WHY: Code quality tooling is part of the project's outer agent harness. A checklist of installs is not a harness. A harness is a system of guides and sensors where each control fires at the right lifecycle stage and produces signals the agent can consume.

After scaffold, invoke (in order):

1. $linter-setup — computational feedback sensors (deterministic, fast, always-on)
2. $harness-setup — full harness inventory (all feedforward guides + all feedback sensors)

Do NOT proceed to $cook until both complete. ($scaffold verification gate enforces this)

Production Readiness Scaffolding (MANDATORY)

Scaffold Production Readiness — See <!-- SYNC:scaffold-production-readiness --> block above for full inline protocol.

Every scaffolded project MUST ATTENTION include these 4 foundations. AI must detect the tech stack from the plan/architecture report and present 2-3 options per concern via a direct user question.

1. Code Quality Tooling

Handled by $linter-setup skill — do NOT duplicate here. Verify completion: check that .editorconfig, linter config, and pre-commit hook config files exist. If missing → block scaffold completion, invoke $linter-setup.

2. Error Handling Foundation

• Detect frontend framework → select from protocol's framework patterns
• Generate: error types, HTTP interceptor, notification service, global error handler
• Minimum 4 files for frontend, 3 for backend-only
• Run protocol's verification checklist

3. Loading State Management

• Detect frontend framework → select from protocol's framework patterns
• Generate: loading service, HTTP loading interceptor, loading indicator component
• Counter-based tracking, 300ms display delay, skip token mechanism
• Run protocol's verification checklist

4. Docker Development Environment

• Always scaffold (unless user explicitly opts out)
• Generate: docker-compose.yml (with profiles), Dockerfile (multi-stage), .dockerignore, .env.example
• Use 127.0.0.1 binding, health checks on all services, non-root user in prod
• Run protocol's verification checklist

Scaffold Handoff from Architecture-Design

If an architecture report exists (from $architecture-design), read the "Scaffold Handoff — Tool Choices" table and use those selections instead of re-asking the user.

OOP/SOLID Compliance Rules (ENFORCE)

1. Single Responsibility — Each base class handles ONE concern
2. Open/Closed — Base classes are extensible via inheritance, closed for modification
3. Liskov Substitution — Concrete implementations are substitutable for their base
4. Interface Segregation — Small, focused interfaces (not one giant IService)
5. Dependency Inversion — All infrastructure behind interfaces, injected via DI

Anti-patterns to prevent:

• God classes combining multiple concerns
• Concrete dependencies (always depend on abstractions)
• Base classes with unused methods that subclasses must override
• Missing generic type parameters where applicable

Adaptation Protocol

The checklists above are templates. Before scaffolding:

1. Read the plan — What tech stack was chosen? (e.g., .NET vs Node.js, Angular vs React)
2. Adapt naming — Match target framework conventions (e.g., C# PascalCase, TypeScript camelCase)
3. Skip irrelevant items — Not every project needs every item (e.g., skip IFileStorageService if no file uploads)
4. Add project-specific items — The plan may require additional base classes not in the template
5. Use a direct user question — Confirm final checklist with user before generating code

Output

After scaffolding is complete:

1. Scaffolding Report — List of all created files with brief descriptions
2. Build Verification — Compilation/type-check passes
3. Architecture Diagram — Optional: generate diagram showing the base class hierarchy
4. Production Readiness Verification — All 4 concern areas verified via protocol checklists
5. Config Files Generated — Linter, formatter, pre-commit, Docker configs all created

Verification Gate (MANDATORY before proceeding to $cook)

Run ALL verification checklists from the production readiness protocol:

• Code quality tooling verified (Section 1)
• Error handling foundation verified (Section 2)
• Loading state management verified (Section 3)
• Docker development environment verified (Section 4)
• $linter-setup completed (linter + formatter + pre-commit + CI gate configured)
• $harness-setup completed (harness-inventory.md produced, feedforward guides in place)

BLOCK proceeding to $cook if ANY verification item fails. Fix issues first, then re-verify.

Next Steps

MANDATORY IMPORTANT MUST ATTENTION — NO EXCEPTIONS after completing this skill, you MUST ATTENTION use a direct user question to present these options. Do NOT skip because the task seems "simple" or "obvious" — the user decides:

• "$cook (Recommended)" — Begin implementing feature stories on top of the scaffolding
• "$workflow-review-changes" — Review scaffolding code before proceeding
• "Skip, continue manually" — user decides

[IMPORTANT] Use task tracking to break ALL work into small tasks BEFORE starting — including tasks for each file read. This prevents context loss from long files. For simple tasks, AI MUST ATTENTION ask user whether to skip.

Evidence Gate: MANDATORY IMPORTANT MUST ATTENTION — every claim, finding, and recommendation requires file:line proof or traced evidence with confidence percentage (>80% to act, <80% must verify first).

Nested Task Expansion Contract — For workflow-step invocation, the [Workflow] ... row is only a parent container; the child skill still creates visible phase tasks.

1. Call the current task list first. If a matching active parent workflow row exists, set nested=true and record parentTaskId; otherwise run standalone.
2. Create one task per declared phase before phase work. When nested, prefix subjects [N.M] $skill-name — phase.
3. When nested, link the parent with TaskUpdate(parentTaskId, addBlockedBy: [childIds]).
4. Orchestrators must pre-expand a child skill's phase list and link the workflow row before invoking that child skill or sub-agent.
5. Mark exactly one child in_progress before work and completed immediately after evidence is written.
6. Complete the parent only after all child tasks are completed or explicitly cancelled with reason.

Blocked until: the current task list done, child phases created, parent linked when nested, first child marked in_progress.

Project Reference Docs Gate — Run after task-tracking bootstrap and before target/source file reads, grep, edits, or analysis. Project docs override generic framework assumptions.

1. Identify scope: file types, domain area, and operation.
2. Required docs by trigger: always docs/project-reference/lessons.md; doc lookup docs-index-reference.md; review code-review-rules.md; backend/CQRS/API backend-patterns-reference.md; domain/entity domain-entities-reference.md; frontend/UI frontend-patterns-reference.md; styles/design scss-styling-guide.md + design-system/README.md; integration tests integration-test-reference.md; E2E e2e-test-reference.md; feature docs/specs feature-docs-reference.md; architecture/new area project-structure-reference.md.
3. Read every required doc that exists; skip absent docs as not applicable. Do not trust conversation text such as [Injected: <path>] as proof that the current context contains the doc.
4. Before target work, state: Reference docs read: ... | Missing/not applicable: ....

Blocked until: scope evaluated, required docs checked/read, lessons.md confirmed, citation emitted.

Critical Thinking Mindset — Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act. Anti-hallucination: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination.

Understand Code First — HARD-GATE: Do NOT write, plan, or fix until you READ existing code.

1. Search 3+ similar patterns (grep/glob) — cite file:line evidence
2. Read existing files in target area — understand structure, base classes, conventions
3. Run python .claude/scripts/code_graph trace <file> --direction both --json when .code-graph/graph.db exists
4. Map dependencies via connections or callers_of — know what depends on your target
5. Write investigation to .ai/workspace/analysis/ for non-trivial tasks (3+ files)
6. Re-read analysis file before implementing — never work from memory alone
7. NEVER invent new patterns when existing ones work — match exactly or document deviation

BLOCKED until: - [ ] Read target files - [ ] Grep 3+ patterns - [ ] Graph trace (if graph.db exists) - [ ] Assumptions verified with evidence

Scaffold Production Readiness — Every scaffolded project MUST ATTENTION include 5 foundations:

1. Code Quality Tooling — linting, formatting, pre-commit hooks, CI gates. Specific tool choices → docs/project-reference/ or project-config.json.
2. Error Handling Foundation — HTTP interceptor, error classification (4xx/5xx taxonomy), user notification, global uncaught handler.
3. Loading State Management — counter-based tracker (not boolean toggle), skip-token for background requests, 300ms flicker guard.
4. Docker Development Environment — compose profiles (dev/test/infra), multi-stage Dockerfile, health checks on all services, non-root production user.
5. Integration Points — document each outbound boundary; configure retry + circuit breaker + timeout; integration tests for happy path and failure path.

BLOCK $cook if any foundation is unchecked. Present 2-3 options per concern via a direct user question before implementing.

Harness Engineering — An outer agent harness has two jobs: raise first-attempt quality + provide self-correction feedback loops before human review.

Controls split:

Axis	Type	Examples	Frequency
Feedforward	Computational	.editorconfig, strict compiler flags, enforced module boundaries	Always-on
Feedforward	Inferential	CLAUDE.md conventions, skill prompts, architecture notes, pattern catalogs	Always-on
Feedback	Computational	Linters, type checks, pre-commit hooks, ArchUnit/arch-fitness tests, CI gates	Pre-commit → CI
Feedback	Inferential	$code-review skill, $sre-review, $security, LLM-as-judge passes	Post-commit → CI

Three harness types:

1. Maintainability — Complexity, duplication, coverage, style. Easiest: rich deterministic tooling.
2. Architecture fitness — Module boundaries, dependency direction, performance budgets, observability conventions.
3. Behaviour — Functional correctness. Hardest: requires approved fixtures or strong spec-first discipline.

Keep quality left: pre-commit sensors fire first (cheap), CI sensors fire second, post-review last (expensive).

Research-driven: Never hardcode tool choices. Detect tech stack → research ecosystem → present top 2-3 options → user decides. Enforce strictest defaults; loosen only with explicit approval.

Harnessability signals: Strong typing, explicit module boundaries, opinionated frameworks = easier to harness. Treat these as greenfield architectural choices, not just style preferences.

AI Mistake Prevention — Failure modes to avoid on every task: Check downstream references before deleting. Deleting components causes documentation and code staleness cascades. Map all referencing files before removal. Verify AI-generated content against actual code. AI hallucinates APIs, class names, and method signatures. Always grep to confirm existence before documenting or referencing. Trace full dependency chain after edits. Changing a definition misses downstream variables and consumers derived from it. Always trace the full chain. Trace ALL code paths when verifying correctness. Confirming code exists is not confirming it executes. Always trace early exits, error branches, and conditional skips — not just happy path. When debugging, ask "whose responsibility?" before fixing. Trace whether bug is in caller (wrong data) or callee (wrong handling). Fix at responsible layer — never patch symptom site. Assume existing values are intentional — ask WHY before changing. Before changing any constant, limit, flag, or pattern: read comments, check git blame, examine surrounding code. Verify ALL affected outputs, not just the first. Changes touching multiple stacks require verifying EVERY output. One green check is not all green checks. Holistic-first debugging — resist nearest-attention trap. When investigating any failure, list EVERY precondition first (config, env vars, DB names, endpoints, DI registrations, data preconditions), then verify each against evidence before forming any code-layer hypothesis. Surgical changes — apply the diff test. Bug fix: every changed line must trace directly to the bug. Don't restyle or improve adjacent code. Enhancement task: implement improvements AND announce them explicitly. Surface ambiguity before coding — don't pick silently. If request has multiple interpretations, present each with effort estimate and ask. Never assume all-records, file-based, or more complex path.

IMPORTANT MUST ATTENTION search 3+ existing patterns and read code BEFORE any modification. Run graph trace when graph.db exists.

IMPORTANT MUST ATTENTION verify all 4 production readiness foundations (quality tooling, error handling, loading state, Docker) before marking scaffold complete.

MUST ATTENTION apply critical thinking — every claim needs traced proof, confidence >80% to act. Anti-hallucination: never present guess as fact.

MUST ATTENTION apply AI mistake prevention — holistic-first debugging, fix at responsible layer, surface ambiguity before coding, re-read files after compaction.

• MANDATORY After task-tracking bootstrap and before target/source work, read required project-reference docs and cite Reference docs read: ....
• MANDATORY Always include lessons.md; project conventions override generic defaults.

• MANDATORY Parent workflow rows do not replace child phase tracking; expand phases and link the parent when nested.
• MANDATORY Orchestrators pre-expand child skill phases before invocation; use [N.M] $skill-name — phase prefixes and one-in_progress discipline.

Prompt-Enhance Closing Anchors

IMPORTANT MUST ATTENTION follow declared step order for this skill; NEVER skip, reorder, or merge steps without explicit user approval IMPORTANT MUST ATTENTION for every step/sub-skill call: set in_progress before execution, set completed after execution IMPORTANT MUST ATTENTION every skipped step MUST include explicit reason; every completed step MUST include concise evidence IMPORTANT MUST ATTENTION if Task tools unavailable, maintain an equivalent step-by-step plan tracker with synchronized statuses

Closing Reminders

MANDATORY IMPORTANT MUST ATTENTION break work into small todo tasks using task tracking BEFORE starting. MANDATORY IMPORTANT MUST ATTENTION validate decisions with user via a direct user question — never auto-decide. MANDATORY IMPORTANT MUST ATTENTION add a final review todo task to verify work quality. MANDATORY IMPORTANT MUST ATTENTION READ the following files before starting:

[TASK-PLANNING] Before acting, analyze task scope and systematically break it into small todo tasks and sub-tasks using task tracking.

[IMPORTANT] Analyze how big the task is and break it into many small todo tasks systematically before starting — this is very important.

Hookless Prompt Protocol Mirror (Auto-Synced)

Source: .claude/hooks/lib/prompt-injections.cjs + .claude/.ck.json

[WORKFLOW-EXECUTION-PROTOCOL] [BLOCKING] Workflow Execution Protocol — MANDATORY IMPORTANT MUST CRITICAL. Do not skip for any reason.

1. DETECT: Match prompt against workflow catalog
2. ANALYZE: Find best-match workflow AND evaluate if a custom step combination would fit better
3. ASK (REQUIRED FORMAT): Use a direct user question with this structure:
   • Question: "Which workflow do you want to activate?"
   • Option 1: "Activate [BestMatch Workflow] (Recommended)"
   • Option 2: "Activate custom workflow: [step1 → step2 → ...]" (include one-line rationale)
4. ACTIVATE (if confirmed): Call $workflow-start <workflowId> for standard; sequence custom steps manually
5. CREATE TASKS: task tracking for ALL workflow steps
6. EXECUTE: Follow each step in sequence [CRITICAL-THINKING-MINDSET] Apply critical thinking, sequential thinking. Every claim needs traced proof, confidence >80% to act. Anti-hallucination principle: Never present guess as fact — cite sources for every claim, admit uncertainty freely, self-check output for errors, cross-reference independently, stay skeptical of own confidence — certainty without evidence root of all hallucination. AI Attention principle (Primacy-Recency): Put the 3 most critical rules at both top and bottom of long prompts/protocols so instruction adherence survives long context windows.

Learned Lessons

Lessons Learned

[CRITICAL] Hard-won project debugging/architecture rules. MUST ATTENTION apply BEFORE forming hypothesis or writing code.

Quick Summary

Goal: Prevent recurrence of known failure patterns — debugging, architecture, naming, AI orchestration, environment.

Top Rules (apply always):

• MUST ATTENTION verify ALL preconditions (config, env, DB names, DI regs) BEFORE code-layer hypothesis
• MUST ATTENTION fix responsible layer — NEVER patch symptom sites with caller-specific defensive code
• MUST ATTENTION use ExecuteInjectScopedAsync for parallel async + repo/UoW — NEVER ExecuteUowTask
• MUST ATTENTION name by PURPOSE not CONTENT — adding member forces rename = abstraction broken
• MUST ATTENTION persist sub-agent findings incrementally after each file — NEVER batch at end
• MUST ATTENTION Windows bash: verify Python alias (where python/where py) — NEVER assume python/python3 resolves

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Debugging & Root Cause Reasoning

• [2026-04-11] Holistic-first: verify environment before code. Failure → list ALL preconditions (config, env vars, DB names, endpoints, DI regs, credentials, permissions, data prerequisites) → verify each via evidence (grep/cat/query) BEFORE code-layer hypothesis. Worst rabbit holes: diving nearest layer while bug sits elsewhere — e.g., hours debugging "sync timeout", real cause: test appsettings pointing wrong DB. Cheapest check first.
• [2026-04-01] Ask "whose responsibility?" before fixing. Trace: bug in caller (wrong data) or callee (wrong handling)? Fix responsible layer — NEVER patch symptom site masking real issue.
• [2026-04-01] Trace data lifecycle, not error site. Follow data: creation → transformation → consumption. Bug usually where data created wrong, not consumed.
• [2026-04-01] Code is caller-agnostic. Functions/handlers/consumers don't know who invokes them. Comments/guards/messages describe business intent — NEVER reference specific callers (tests, seeders, scripts).

Architecture Invariants

• [2026-03-31] ParallelAsync + repo/UoW MUST use ExecuteInjectScopedAsync, NEVER ExecuteUowTask. ExecuteUowTask creates new UoW but reuses outer DI scope (same DbContext) — parallel iterations sharing non-thread-safe DbContext silently corrupt data. ExecuteInjectScopedAsync creates new UoW + new DI scope (fresh repo per iteration).
• [2026-03-31] Bus message naming MUST include service name prefix — core services NEVER consume feature events. Prefix declares schema ownership (AccountUserEntityEventBusMessage = Accounts owns). Core services (Accounts, Communication) are leaders. Feature services (Growth, Talents) sending to core MUST use {CoreServiceName}...RequestBusMessage — never define own event for core to consume.

Naming & Abstraction

• [2026-04-12] Name PURPOSE not CONTENT — "OrXxx" anti-pattern. HrManagerOrHrOrPayrollHrOperationsPolicy names set members, not what it guards. Add role → rename = broken abstraction. Rule: names express DOES/GUARDS, not CONTAINS. Test: adding/removing member forces rename? YES = content-driven = bad → rename to purpose (e.g., HrOperationsAccessPolicy). Nuance: "Or" fine in behavioral idioms (FirstOrDefault, SuccessOrThrow) — expresses HAPPENS, not membership.

Environment & Tooling

• [2026-04-20] Windows bash: NEVER assume python/python3 resolves — verify alias first. Python may not be in bash PATH under those names. Check: where python / where py. Prefer py (Windows Python Launcher) for one-liners, node if JS alternative exists.

Test-specific lessons → docs/project-reference/integration-test-reference.md Lessons Learned section. Production-code anti-patterns → docs/project-reference/backend-patterns-reference.md Anti-Patterns section. Generic debugging/refactoring reminders → System Lessons in .claude/hooks/lib/prompt-injections.cjs.

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Closing Reminders

• IMPORTANT MUST ATTENTION holistic-first: verify ALL preconditions (config, env, DB names, endpoints, DI regs) BEFORE code-layer hypothesis — cheapest check first
• IMPORTANT MUST ATTENTION fix responsible layer — NEVER patch symptom site; trace caller (wrong data) vs callee (wrong handling), fix root owner
• IMPORTANT MUST ATTENTION parallel async + repo/UoW → ALWAYS ExecuteInjectScopedAsync, NEVER ExecuteUowTask (shared DbContext = silent data corruption)
• IMPORTANT MUST ATTENTION bus message prefix = schema ownership; feature services NEVER define events for core services — use {CoreServiceName}...RequestBusMessage
• IMPORTANT MUST ATTENTION name by PURPOSE — adding/removing member forces rename = broken abstraction
• IMPORTANT MUST ATTENTION sub-agents MUST write findings after each file/section — NEVER batch all findings into one final write
• IMPORTANT MUST ATTENTION Windows bash: NEVER assume python/python3 resolves — run where python/where py first, use py launcher or node

[LESSON-LEARNED-REMINDER] [BLOCKING] Task Planning & Continuous Improvement — MANDATORY. Do not skip.

Break work into small tasks (task tracking) before starting. Add final task: "Analyze AI mistakes & lessons learned".

Extract lessons — ROOT CAUSE ONLY, not symptom fixes:

1. Name the FAILURE MODE (reasoning/assumption failure), not symptom — "assumed API existed without reading source" not "used wrong enum value".
2. Generality test: does this failure mode apply to ≥3 contexts/codebases? If not, abstract one level up.
3. Write as a universal rule — strip project-specific names/paths/classes. Useful on any codebase.
4. Consolidate: multiple mistakes sharing one failure mode → ONE lesson.
5. Recurrence gate: "Would this recur in future session WITHOUT this reminder?" — No → skip $learn.
6. Auto-fix gate: "Could $code-review/$code-simplifier/$security/$lint catch this?" — Yes → improve review skill instead.
7. BOTH gates pass → ask user to run $learn. [TASK-PLANNING] [MANDATORY] BEFORE executing any workflow or skill step, create/update task tracking for all planned steps, then keep it synchronized as each step starts/completes.