Game Artist MCP

An AI-native deterministic game-art workstation for agent hosts.

Game Artist is not another general MCP control plane and does not use a generative image model as its core art engine.

Its job is to give an LLM explicit game-art operations:

LLM
 ↓
Game Artist MCP
 ↓
Art IR / explicit geometry
 ↓
render
 ↓
visual inspection
 ↓
targeted edit
 ↓
game-ready asset

Relationship to FolderForge

FolderForge is the preferred production host/control plane:

ChatGPT / MCP host
        ↓
    FolderForge
        ↓
   Game Artist
        ↓
 deterministic art core

FolderForge owns generic infrastructure such as transport, authentication, policy, audit, sandboxing, plugin lifecycle and broad Godot control.

Game Artist owns art-domain capabilities such as vector/cutout representation, pivots, animation recipes, style constraints and art QA.

The core remains usable directly through MCP without FolderForge.

See:

• ADR-0001

• Roadmap

• POC-001

• POC-002

Related MCP server: frameforge-mcp

Current state

• POC-001/002: deterministic vector art engine and 11-tool stdio MCP with FolderForge integration.

• POC-003: render → image inspection → targeted edit loop (mechanics only).

• POC-004: Spirit Lantern cutout/Godot exporter and headless runtime verification.

• POC-005A: ArtStyleProfile, safe structural evidence auditor, and three agent-directed local MCP trials (cultivation sword, medicinal pouch, stone censer) under benchmarks/poc005a/runs. Each preserves two actual PNG renders and a correction on the same asset. Their local structural audit is included in npm test.

Evidence boundary: The three live sessions were executed through a local stdio MCP transport, not an independently audited provider-origin agent host. Their image critique is SELF_REVIEW. The repository therefore retains AGENT_PROVENANCE_PENDING and does not claim artistic FULL_PASS, independent aesthetics approval or production art quality. See POC-005A benchmark protocol.

POC-005B is merged: opt-in material-aware Art IR, deterministic gradient/hand-directed surface marks/bounded glow, plus controlled same-geometry 64/128-pixel A/B review bundles for those three earlier props. The review bundles are UNSCORED. A fourth original compass asset was constructed through a new self-selected local MCP session (not an evaluator-supplied held-out prompt): 28 nodes, 14 MCP calls, 3 rendered previews and 2 image-grounded corrections. The latest correction restored an open suspension loop that an inappropriate appearance fill made visually solid. Historical revision-2 media are preserved. Technical and style gates pass, but external authorship attestation and independent visual scoring remain pending. See POC-005B review protocol and latest handoff.

Hard limits: Material-aware Godot export is currently unsupported (UNSUPPORTED_GODOT_APPEARANCE), even though the legacy Spirit Lantern passes headless Godot. Green CI proves technical behavior, not aesthetic quality, autonomy or production art readiness.

Local development

Requirements:

• Node.js 22+

• rsvg-convert from librsvg for PNG previews

Run the raw MCP server:

node src/mcp/server.mjs --workspace ./.game-artist

Run the direct protocol smoke:

npm run smoke:mcp

To verify the FolderForge integration before the compatible package is published, build the exact source revision used by CI:

git clone https://github.com/roronoazoroshao369/FolderForge.git ../FolderForge
git -C ../FolderForge checkout 59c1096167a81bef24a07fa88453f5c50e0fe64a
npm --prefix ../FolderForge ci --ignore-scripts
npm --prefix ../FolderForge run build
node ../FolderForge/dist/main.js plugin validate .
node ../FolderForge/dist/main.js plugin test . --call health --args-json '{}'

Do not infer npm availability from FolderForge's source package.json; POC-002 pins source evidence until a compatible public package is actually published.

POC-005C1 (implemented technical workflow, still UNSCORED): Offline Hybrid Independent Visual Evaluation now reconstructs three actual baseline/enhanced props, checks geometry and 64/128px PNG bytes, creates reviewer-only offline A/B packages, accepts evaluator-verified blind human scoring, locks forms before mapping reveal and computes deterministic VISUAL_GO/ARTISTIC_NO_GO/REVIEW_PENDING. AI critic input is ADVISORY_ONLY, never a human reviewer. Run npm run poc:005c1:dry to generate an UNSCORED CI reviewer kit; its result must stay TECHNICAL_PASS, REVIEW_PENDING, and zero independent reviewers. Source: spec, TDD plan, reviewer instructions. The shipped implementation was checked by SELF_REVIEW because no separate subagent/code-review tool was exposed; do not mislabel that as independent code review.

POC-005C1 trust-boundary follow-up (PR #19): The offline reviewer must now explicitly attest HUMAN/NOT_ART_AUTHOR/NOT_EXPOSED; evaluator verification must bind to the same frozen session/package and acknowledgement timestamp, and a separate distinct out-of-band evidence reference is required for each reviewer. Previous reviewer kits without the declaration are incompatible: issue a NEW frozen review session; never manufacture or retroactively edit human attestations. Mechanical tests do not prove reviewer identity or artwork merit.

Next external evidence gate: obtain at least one real independent non-author human blind evaluation at 64px/128px (ideally two, frozen quorum), and independently obtain a provider-attested image-visible agent run on an evaluator-assigned new brief (separate POC-005C2). No human visual scores or provider-origin attestations have been supplied; the repository MUST retain VISUAL_REVIEW_PENDING / AGENT_PROVENANCE_PENDING until authentic evidence exists. A green CI or a synthetic fixture is not artistic GO or production-readiness proof.