AGENTS.md@extensions/Godot-AI-Tilemap git:20261016.cf84037A

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# AGENTS.md — Godot-AI-Tilemap

A **Godot-MCP extension**: MCP tools for Godot's built-in `TileMapLayer` node (Godot 4.3+, the modern
replacement for the deprecated `TileMap`) and its `TileSet`. Shipped as a **source-only NuGet package**
(`com.IvanMurzak.Godot.MCP.Tilemap`) that compiles inside the consumer's Godot project against the consumer's
own GodotSharp. Created from
[`Godot-AI-Tools-Template`](https://github.com/IvanMurzak/Godot-MCP/tree/main/templates/extension). The packaging recipe is
the load-bearing detail — read `docs/source-only-nuget-recipe.md`.

## Layout

- `src/Godot-AI-Tilemap/` — the source-only package (`Godot.NET.Sdk`):
  - `Runtime/Tools/` — `Tool_Tilemap.cs` (the `[AiToolType]` partial class), `Tool_Tilemap.Ids.cs` (all
    tool-id consts, pinned by tests).
  - `Runtime/Tilemap/` — pure-managed cell / atlas-coordinate parsing + validation (`TileCell`,
    `TilemapValidation`, `TileMapLayerInfo`), all unit-tested.
  - `Editor/Tools/` — one file per editor tool (`Tool_Tilemap.<Name>.cs`) + shared helpers in
    `Tool_Tilemap.Editor.cs`; all behind `#if TOOLS`.
  - `build/com.IvanMurzak.Godot.MCP.Tilemap.props` — source-injection props, auto-imported by NuGet in the
    consumer; MUST stay named `<PackageId>.props`.
- `tests/Godot-AI-Tilemap.Tests/` — xUnit specs for the pure-managed sources only (no Godot binary).
- `tests/e2e/` — live `run-tool` E2E: the tool list `e2e-tools.json`, driven by `run_tool_e2e.py`.
- `testbed/Tilemap-Testbed.csproj` — consumer `Godot.NET.Sdk` project restoring the local-packed package; its
  `dotnet build` is the source-injection proof.
- `commands/` — `bump-version`, `update-core`, `init` (`.ps1` + `.py`), `get-version.ps1`.
- CI and publishing are centralized in the monorepo; see `../../docs/EXTENSION-MONOREPO.md`.

- `docs/` — `source-only-nuget-recipe.md` (the packaging recipe + consumer story); `ci.md` (workflows, version
  gate, multi-Godot matrix, NuGet publishing setup).

## Tools

Ids live in `Runtime/Tools/Tool_Tilemap.Ids.cs` (the source of truth). Current tools: `tilemap-create`,
`tilemap-set-tileset`, `tilemap-set-cell`, `tilemap-erase-cell`, `tilemap-get-used-cells`, `tilemap-clear`.

## Build / test (no Godot binary)

```bash
dotnet build src/Godot-AI-Tilemap/Godot-AI-Tilemap.csproj  # source-only package compiles tools
dotnet test  tests/Godot-AI-Tilemap.Tests/Godot-AI-Tilemap.Tests.csproj
dotnet pack  src/Godot-AI-Tilemap/Godot-AI-Tilemap.csproj -p:Version=0.0.0-ci -o local-nuget
dotnet build testbed/Tilemap-Testbed.csproj                # consumes the local package (injection proof)
```

`Godot.NET.Sdk` supplies GodotSharp from NuGet, so build/test/pack and the source-injection proof need no
Godot install (the testbed build is a faithful proxy for `godot --build-solutions`). CI proves the recipe
across Godot 4.3 / 4.4 / 4.5 (the central monorepo SDK matrix). `dotnet pack` reuses the **global NuGet
cache** for an already-cached version: when re-packing the same `Version`, clear
`~/.nuget/packages/com.ivanmurzak.godot.mcp.tilemap/<ver>` (or pack a unique version) before re-restoring the
testbed, or you silently build the stale cached source.

## Conventions

- Root namespace `com.IvanMurzak.Godot.MCP.Tilemap`. Every `.cs` starts with the Apache-2.0 header.
- Pure-managed code (no Godot native API) → `Runtime/` (outside `#if TOOLS`, unit-testable); editor-driving
  tools → `Editor/` (behind `#if TOOLS`, every Godot call via `MainThread.Instance.Run(...)`, E2E-verified).
- Godot types that wrap a native object (`Node`, `Resource`, `NodePath`, `SceneTree`) P/Invoke on
  construction, so they must never be touched from the no-Godot xUnit host — keep them out of `Runtime/`.
- The package declares ONLY the `com.IvanMurzak.McpPlugin` / `com.IvanMurzak.ReflectorNet` min-version deps;
  **GodotSharp must never become a package dependency** (CI asserts the nuspec). Keep the MCP pins in lockstep
  with the core Godot-MCP addon; bump with `commands/update-core.ps1`.
- One `[AiToolType] partial class Tool_Tilemap`; one `[AiTool]` method per partial-class file. Add every new
  pure-managed source to the test csproj `<Compile Include>` list so it is unit-tested.