# Compile Error Guidance - Reusable Protocol
**Last Updated:** 2026-04-05

Apply this protocol for all compile issues.

## 1) Verify First
- [ ] Verify exact NinjaScript/API signature against official NT8 docs before editing: `https://developer.ninjatrader.com/docs/desktop`.
- [ ] Confirm file is in scope before making any change.

## 2) Classify the Error
- [ ] Missing type/namespace (e.g., `CS0246`).
- [ ] Invalid override/signature/access modifier (e.g., `CS0115`, `CS0507`).
- [ ] Argument mismatch or wrong overload (e.g., `CS1503`).
- [ ] C# language version incompatibility (C# 6+ syntax in C# 5 project).

## 3) Apply Smallest Safe Fix
- [ ] Prefer minimal edits in scoped files only.
- [ ] Fix root cause, not symptom chaining.
- [ ] Preserve existing architecture/contracts unless task explicitly requires change.

## 4) Re-Run Verification
- [ ] Run `.\verify-build.bat`.
- [ ] Run required tests for changed area.
- [ ] If NinjaScript touched, run NT8 compile check in NinjaScript Editor.

## 5) Capture Durable Learning
For non-trivial compile failures, add concise entries to:
- [ ] `docs/00-governance/common_failures.md` (error fingerprint + fix).
- [ ] `docs/00-governance/compile_guardrails.md` (prevention rule).
- [ ] `docs/00-governance/patterns_and_antipatterns.md` (good vs bad pattern).

## Do Not
- [ ] Do not guess signatures, overloads, enums, or attributes.
- [ ] Do not invent placeholder enums/types unless confirmed by domain/task requirements.
- [ ] Do not keep one-off incident dumps in this rule file; store incidents in `common_failures.md`.