Pierre-Marie Charavel
93ca33c36a
- ue_parser.py: position-based UE C++ header parser - ue_markdown.py: compact agent-optimised Markdown renderer - generate.py: two-pass CLI (parse-all → type index → render-all) - samples/: representative UE headers (GeomUtils, AIController, GameplayTagsManager) - .claude/skills/ue-api/: Claude Code skill for querying UE docs + source headers - CLAUDE.md: architecture notes, usage, critical gotchas Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
110 lines
4.2 KiB
Markdown
110 lines
4.2 KiB
Markdown
---
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name: ue-api
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description: >
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Use this skill when the user asks anything about Unreal Engine C++ APIs,
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class hierarchies, system flows, or how engine subsystems work together.
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Trigger phrases include: "how does X work in UE", "what is the flow for",
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"which class handles", "what virtual functions", "UE API for", "Unreal Engine
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architecture", and any question that names UE types like ACharacter,
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UActorComponent, APlayerController, UBehaviorTreeComponent, APawn, etc.
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Always use this skill for Unreal Engine questions — don't rely on training
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data alone when local documentation is available.
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---
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# UE API Skill
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Answer questions about Unreal Engine C++ APIs and system flows using the local
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documentation corpus as the fast primary source, then source headers for depth.
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## Configuration
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Two environment variables control where to look:
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| Variable | Purpose | Example |
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|---|---|---|
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| `UE_DOCS_PATH` | Root of the generated documentation | `/home/user/ue-docs` |
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| `UE_ENGINE_ROOT` | UE engine source root (for header fallback) | `/home/user/UnrealEngine` |
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**Resolve them at the start of every query:**
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```bash
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echo "$UE_DOCS_PATH"
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echo "$UE_ENGINE_ROOT"
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```
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If `UE_DOCS_PATH` is unset, ask the user where their generated docs are before
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proceeding. If `UE_ENGINE_ROOT` is unset, only ask when a question actually
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requires source headers — don't interrupt doc-only queries.
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The type index is always at `$UE_DOCS_PATH/type-index.txt`.
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## Step 1 — Identify types, resolve paths
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Extract UE type names from the question (e.g. `APlayerController`, `APawn`,
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`UBehaviorTreeComponent`). Resolve all of them in a single grep:
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```bash
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grep "^APlayerController:\|^APawn:\|^ACharacter:" "$UE_DOCS_PATH/type-index.txt"
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```
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Paths in the index are relative to `$UE_DOCS_PATH` — prepend it when reading:
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```bash
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# index returns: AController: Engine/Classes/GameFramework/Controller.md
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# read as:
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Read "$UE_DOCS_PATH/Engine/Classes/GameFramework/Controller.md"
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```
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The `.md` files are compact by design — only items with C++ doc comments,
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no deprecated entries, enums collapsed when undescribed.
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## Step 2 — Follow the trail
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Inline links in `*Inherits*:` lines and function signatures point to related
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types. Follow them when the question spans multiple classes. A second grep on
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`type-index.txt` is always cheaper than guessing paths.
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## Step 3 — Escalate to source headers when docs aren't enough
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The docs only surface items with C++ doc comments. Go to `.h` files when:
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- The exact call order or implementation logic isn't described in any comment
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- A function or member is absent from `.md` files (no doc comment)
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- The question involves macros: `UCLASS`, `UPROPERTY`, `UFUNCTION`,
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`DECLARE_DELEGATE_*`, `GENERATED_BODY`, etc.
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- Private or protected members are relevant to the answer
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- The user asks about edge-case behaviour ("what happens when X is null?")
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Search under `$UE_ENGINE_ROOT/Engine/Source/` — e.g.:
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```bash
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Glob("**/*Controller*.h", path="$UE_ENGINE_ROOT/Engine/Source/Runtime/Engine")
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Grep("void Possess", path="$UE_ENGINE_ROOT/Engine/Source")
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```
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## Output format
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Lead with the direct answer or a concise flow description. For multi-step
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flows use an ASCII sequence or numbered list. For single-class API questions,
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a brief prose answer with the key function signatures is enough.
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Cite every substantive claim — `(Controller.md)` for docs, `(Controller.h:142)`
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for source. Mark source-derived facts as *implementation detail* since they can
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change across engine versions; doc-derived facts reflect the stable API contract.
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## Examples
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**"How does APlayerController possess APawn?"**
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→ check `$UE_DOCS_PATH` → grep type-index for AController, APawn,
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APlayerController, ACharacter → read the four `.md` files → ASCII diagram
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**"What virtual functions does ACharacter expose for movement?"**
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→ grep for ACharacter, UCharacterMovementComponent → read docs → list virtuals
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**"What does UFUNCTION(BlueprintCallable) expand to?"**
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→ docs won't help (macro) → search `$UE_ENGINE_ROOT` for `UFUNCTION` definition
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**"How does the behavior tree pick which task to run?"**
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→ grep for UBehaviorTreeComponent, UBTCompositeNode, UBTDecorator → read docs
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→ if execution order is still unclear, escalate to `BehaviorTreeComponent.h`
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