- Use `build.py c++` for lightweight C++ rebuilds, `build.py all` for full rebuilds.
- Does a lot of refactoring in early development stages. Be ready for frequent renames, restructuring, and changes of mind without pushback.
- VS Code is the IDE. Use `code --goto <filename>:<line>` to open files/locations in the IDE instead of showing code snippets at the prompt.
- When asked to "show me" code, open it in VS Code rather than pasting it in the terminal.
- The Unreal Engine source for this project lives at `/home/jyelon/integration.UE` (sibling to the project dir), not `~/UnrealEngine`. Always use this copy when working on the integration project.
- Many of Unreal's basic data types (FString, TArray, TSet, TMap, etc.) are in `integration.UE/Engine/Source/Runtime/Core/Public/Containers/`.
- Editor log files are at `integration/User/jyelon/Saved/Logs/`.
## Critical: Minimize Diff Noise
- The user reviews all changes via `git diff` in VS Code. Every unnecessary diff line costs review time.
- **Preserve all existing comments.** Comments describe the logic, not the syntax — they survive refactors. Only remove a comment if the code it described was genuinely deleted.
- **Don't rename variables, reorder code, or reformat lines** unless directly required by the task. If a variable name works, leave it. If a comment is in the right place, don't move it.
- Don't make gratuitous changes. If it doesn't need to change, don't touch it.
- **No FREE-FLOATING (file-scope) static functions in Unreal code.** Use class methods (incl. `static` member functions) or namespace-scoped functions instead. A `static` member function inside a class is fine — e.g. a Blueprint-callable factory. The rule is only against file-local `static` free functions. (Corrected 2026-05-26 after I misread this as banning all `static`.)
- Prefer in-class member initializers (`int x_ = 0;` in the header) over explicit initialization in constructor bodies. When touching constructors, migrate toward this style.
- Inline empty constructors/destructors in the header when possible.
- Avoid ternary operator unless very concise (e.g., `x ? 1 : 0`). For longer expressions, use early-return `if` instead.
- When asked for a small change, do exactly that. If it turns out to require broader refactoring, STOP and explain the situation instead of silently rewriting the module.
## Tools
-`tools/clangd-query.py` — Query clangd for C++ symbols. Uses a background daemon for fast responses after first invocation (~10s cold, milliseconds warm). Commands:
-`python3 tools/clangd-query.py symbol <name>` — Find symbols by name across the whole project.
-`python3 tools/clangd-query.py definition <file> <line> <col>` — Go to definition (1-based line/col).
- UE Wingman is a command-line tool (no longer an MCP server). Plugin lives in `Plugins/UEWingman/`; CLI is `ue-wingman` (on PATH at `/home/jyelon/bin/ue-wingman`).
- Invoke directly via Bash. Subcommands are CamelCase, e.g. `ue-wingman Graph_Dump <path> True`.
- Start by reading the manual: `ue-wingman Documentation_Manual`. Also useful: `Documentation_Commands` (concise list), `Documentation_Command <Name>` (detailed help for one command).
- Fetcher path syntax: `/Game/<Asset>,graph:<GraphName>,node:<NodeId>,pin:<PinName>` (also `widget:`, `component:`, `levelblueprint:`, `structprop:`). FNames in paths use periods for spaces (e.g. `graph:Handle.Invalid.Lua.Command`, not `HandleInvalidLuaCommand`). Other marks `\"'(),.:;<=>&` use HTML entity escapes like ` `.
- ue-wingman is much faster than the LLM — batch multiple commands with `;` instead of running one at a time.
## Project
- [Eris addinfo intentionally removed](project_eris_addinfo_removed.md) — `luaG_runerror` no longer prefixes `file:line:`; traceback machinery handles location info
- [LLDB formatter style — no defensive IsValid checks](feedback_lldb_formatter_no_defensive_checks.md) — let invalid SBValues fail loudly; silent returns conceal bugs
- [C++ never depends on Blueprint](feedback_cpp_no_bp_dependency.md) — construct widget trees in C++; don't reference WBP assets from C++
- [Prefer check() over silent-skip](feedback_check_over_silent_skip.md) — invariants use check(); silent continue/return hides bugs
- [Don't auto-build after every change](feedback_dont_auto_build.md) — only build when the user asks
- [Edit workspace template, not the generated file](feedback_workspace_template.md) — `Integration.code-workspace` is generated; edit `Integration.code-workspace.tpl.json`