Authoritative ato authoring and review skill: language reference, stdlib, design patterns, and end-to-end board design workflow.

How FabLL (faebryk.core.node) maps Python node/trait declarations into the TypeGraph + instance graph, including field/trait invariants and instantiation patterns. Use when defining new components or traits, working with the Node API, or understanding type registration.

LLM-focused workflow for working in this repo: compile Zig, run the orchestrated test runner, consume test-report.json/html artifacts, and discover/debug ConfigFlags.

How the Zig S-expression engine and typed KiCad models work, how they are exposed to Python (pyzig_sexp), and the invariants around parsing, formatting, and freeing. Use when working with KiCad file parsing, S-expression generation, or layout sync.

How the Zig-backed instance graph works (GraphView/NodeReference/EdgeReference), the real Python API surface, and the invariants around allocation, attributes, and cleanup. Use when working with low-level graph APIs, memory management, or building systems that traverse the instance graph.

How the Zig↔Python binding layer works (pyzig), including build-on-import, wrapper generation patterns, ownership rules, and where to add new exported APIs. Use when adding Zig-Python bindings, modifying native extensions, or debugging C-API interactions.

How the Faebryk parameter solver works (Sets/Literals, Parameters, Expressions), the core invariants enforced during mutation, and practical workflows for debugging and extending the solver. Use when implementing or modifying constraint solving, parameter bounds, or debugging expression simplification.

How Faebryk's TypeGraph works (GraphView + Zig edges), how to traverse/resolve references, and how FabLL types/traits map onto edge types. Use when working with TypeGraph traversal, edge types, or building type-aware queries.

Spec-driven planning for complex design tasks: when to plan, how to write specs as .ato files, and how to verify against requirements.

How the Faebryk component library is structured, how `_F.py` is generated, and the conventions/invariants for adding new library modules. Use when adding or modifying library components, traits, or module definitions.

Frontend standards for atopile extension webviews: architecture, contracts, design system, and testing workflow.

How the atopile compiler builds and links TypeGraphs from `.ato` (ANTLR front-end → AST → TypeGraph → Linker → DeferredExecutor), plus the key invariants and test entrypoints. Use when modifying the compiler pipeline, grammar, AST visitors, or type resolution.

LLM-focused code review process for this repo: what to check, how to ground feedback in invariants/tests, and how to verify changes efficiently (including test-report.json).

Reference for the `.ato` declarative DSL: type system, connection semantics, constraint model, and standard library. Use when authoring or reviewing `.ato` code.

Generate short live progress summaries for the atopile agent from recent tool events, preambles, checklist changes, and build state. Use for ephemeral UI activity text only, never for transcript replies or autonomous reasoning.

How to write and maintain `.claude/skills/*/SKILL.md` files: source-of-truth-first process, verification steps, and conventions.

Core runtime behavior for the atopile sidebar agent: identity, persistence model, execution rules, and tool recipes.

How the atopile Language Server works (pygls), how it builds per-document graphs for completion/hover/defs, and the invariants for keeping it fast and crash-proof.