Claude-Code-Game-Studios/CCGS Skill Testing Framework/agents/engine/godot/godot-shader-specialist.md

Agent Test Spec: godot-shader-specialist

Agent Summary

Domain: Godot shading language (GLSL-derivative), visual shaders (VisualShader graph), material setup, particle shaders, and post-processing effects. Does NOT own: gameplay code, art style direction. No gate IDs assigned.

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Static Assertions (Structural)

• description: field is present and domain-specific (references Godot shading language / materials / post-processing)
• tools: list includes Read, Write, Edit, Glob, Grep
• Model tier is sonnet — frontmatter model: reads exactly sonnet (tiers: .claude/docs/model-tiers.md)
• Agent definition references docs/engine-reference/godot/VERSION.md as the authoritative source for Godot shader API changes

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Test Cases

Case 1: In-domain request — appropriate output

Input: "Write a dissolve effect shader for enemy death in Godot." Expected behavior:

• Produces valid Godot shading language code (not HLSL, not GLSL directly)
• Uses shader_type spatial; or canvas_item as appropriate
• Defines uniform float dissolve_amount : hint_range(0.0, 1.0);
• Samples a noise texture to determine per-pixel dissolve threshold
• Uses discard; for pixels below the threshold
• Optionally adds an edge glow using emission near the dissolve boundary
• Code is syntactically correct for Godot's shading language

Case 2: HLSL redirect

Input: "Write an HLSL compute shader for this dissolve effect." Expected behavior:

• Does NOT produce HLSL code
• States that Godot materials are written in Godot's own shading language (.gdshader, a GLSL derivative), not HLSL
• Translates the HLSL intent into the equivalent .gdshader approach (noise threshold, discard, emission at the dissolve edge)
• If a compute shader was really the intent, flags compute as a separate low-level path (RenderingDevice; unavailable on the Compatibility renderer) and brings in godot-gdextension-specialist for compute-shader offloading

Case 3: Post-cutoff API change — shader texture types (Godot 4.4)

Input: "Use texture() with a sampler2D to sample the noise texture in the shader." Expected behavior:

• Checks the version reference before writing the shader (VERSION.md, then breaking-changes.md and modules/rendering.md)
• Identifies what the 4.4 change covers: engine-side shader texture parameter/return types moved from Texture2D to Texture — script and engine API code that handles shader textures, not shading-language syntax
• Uses uniform sampler2D noise_texture; with texture(noise_texture, UV) — the form its own patterns use; the reference records no change to shading-language sampling syntax
• Does NOT invent a changed sampling syntax for 4.4–4.6, or rewrite sampler2D / texture() because of the 4.4 row

Case 4: Fragment shader LOD strategy

Input: "The fragment shader for the water surface has 8 texture samples and is causing GPU bottlenecks on mid-range hardware." Expected behavior:

• Identifies the per-fragment texture sample count as the primary cost driver
• Proposes an LOD strategy:
  • Reduce sample count at distance with a simplified LOD material for distant water, not a per-pixel distance branch in the fragment shader
  • Move UV/scroll math that does not need per-pixel evaluation into the vertex shader and pass it through a varying
  • Make sure the water textures are mipmapped (e.g. filter_linear_mipmap) so distant samples read smaller mip levels
• Provides the shader code modification implementing the LOD approach
• Does NOT change gameplay behavior of the water system

Case 5: Context pass — Godot 4.6 glow rework

Input: Engine version context: Godot 4.6. Request: "Add a bloom/glow post-processing effect to the scene." Expected behavior:

• References the VERSION.md note: Godot 4.6 includes a glow rework
• Because VERSION.md records Installed at pin time as NOT DETERMINED, asks which editor version is installed before tuning for the 4.6 glow behavior
• Produces glow configuration guidance on the WorldEnvironment node's Environment resource
• States the documented 4.6 change: glow now processes before tonemapping (it was after), with screen blending — so glow intensity/blend tuned on an earlier version will look different and may need re-tuning
• Does NOT invent renamed or removed glow properties that breaking-changes.md and modules/rendering.md do not document
• Flags any properties that the LLM's training data may have incorrect information about due to the post-cutoff timing

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Protocol Compliance

• Stays within declared domain (Godot shading language, materials, VFX shaders, post-processing)
• Redirects gameplay code requests to gameplay-programmer
• Writes material and post-process shaders as .gdshader (Godot shading language) — never HLSL
• Checks engine version reference for post-cutoff shader API changes (4.4 texture types, 4.6 glow rework)
• Returns structured output (shader code with uniforms documented, LOD strategies with performance rationale)
• Flags any post-cutoff API usage as requiring verification
• Asks "May I write this to [filepath]?" naming the file before writing

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Coverage Notes

• Dissolve shader (Case 1) should be paired with a visual test screenshot in production/qa/evidence/
• Texture-type case (Case 3) confirms the agent reads what a post-cutoff change actually covers before applying it, instead of rewriting syntax the change does not touch
• Glow rework (Case 5) is a Godot 4.6-specific test — verifies the agent applies the most recent migration notes