asset-spec
Per-asset visual specs plus AI generation prompts from GDDs and character profiles. After the art bible.
How do I install this agent skill?
npx skills add https://github.com/donchitos/claude-code-game-studios --skill asset-specIs this agent skill safe to install?
- Gen Agent Trust Hubpass
The skill automates asset specification generation by parsing design documents and spawning specialist agents. It is generally safe but carries a low risk of indirect prompt injection from the documents it processes and uses dynamic context injection for configuration purposes.
- Socketpass
No alerts
- Snykpass
Risk: LOW · No issues
- ZeroLeakspass
Score: 93/100 · 2 sections analyzed
What does this agent skill do?
!bash "${CLAUDE_SKILL_DIR}/../../hooks/yaml-helper.sh" resolve_config --keys review_mode,automation
If no argument is provided, check whether design/assets/entity-inventory.md exists:
- If it exists: read it, find the first entity or screen with status "Needed" but no spec file yet, and use
AskUserQuestion:- Prompt: "The next unspecced item is [name]. Generate specs for it?"
- Options:
[A] Yes — spec [name]/[B] Pick a different item/[C] Stop here
- If no entity inventory: check
design/assets/asset-manifest.md. If manifest exists, same flow above but reading from manifest. - If neither exists: start the Entity & Screen Inventory flow (Phase 0b below) rather than failing.
Every AskUserQuestion call follows .claude/docs/automation-modes.md
(collaborative asks always · guided major-only · autonomous logs and proceeds;
automation_always_ask categories always prompt). Note: actually invoking an external image
generator (calling an image API) always prompts regardless of
modes.automation — it is an irreversible external action guarded
unconditionally, independent of whether external_calls is listed in
automation_always_ask. (Today this skill only emits generation-prompt
text; the guard applies if live generation is ever wired in.)
Phase 0b: Entity & Screen Inventory (runs when no arguments and no existing inventory)
This flow produces design/assets/entity-inventory.md — the master list of everything
the game needs visually. Run once before asset spec work begins.
Step 1 — Gather from docs
Read all available source material in parallel:
design/gdd/systems-index.md— extract every system listed- GDD asset content — do not full-read every GDD. The two wanted sections are
standard headings, and named entities live in the registry:
For named entities (characters, enemies, buildings, items), readGrep pattern="## (Visual/Audio Requirements|UI Requirements)" glob="design/gdd/*.md" output_mode="content" -A 25design/registry/entities.yaml(entities/items) if it exists and has entries; otherwise grep the GDDs for named content. Full-read a GDD only when its Visual/Audio section is missing or reads[To be designed](Phase 1 already handles that case). VFX events surface in the Visual/Audio grep context. design/art/art-bible.md— extract: any named visual categories, asset type expectationsdesign/narrative/— scan for any character or world entity documents if they exist (optional — not required)
Step 2 — Build proposed inventory
Organize everything found into categories:
Characters / Protagonists
Enemies / Creatures
Buildings / Structures
Environment / Terrain
Items / Props
VFX / Particles
UI Screens (list each screen by name)
HUD Elements
Audio (SFX, music — descriptions only, no generation prompts)
Other
For each item, note the source doc it was found in.
Step 3 — Present and collaborate
Present the full proposed inventory to the user in conversation. Then use AskUserQuestion:
- Prompt: "I found [N] visual entities and [N] UI screens across your GDDs and art bible. Review the list — what's missing, what's not needed?"
- Options:
[A] Looks good — save this inventory[B] Add items I'll describe[C] Remove items that don't apply[D] Both add and remove — let me edit
If [B] or [D]: ask the user to describe additional items. Accept brief descriptions ("a medieval keep, used as a level background") or detailed ones — either works. Work through them collaboratively until the user is satisfied.
If [C] or [D]: ask which items to remove and why. Remove them from the list.
Step 4 — Write inventory
After user approval, ask: "May I write the entity inventory to design/assets/entity-inventory.md?"
Write the file:
# Visual Entity & Screen Inventory
> Generated: [date]
> Sources: [list of source docs read]
## Entities
| # | Name | Type | Description | Source | Status |
|---|------|------|-------------|--------|--------|
| 1 | [name] | Character / Enemy / Building / Environment / Item / Other | [brief description] | [source doc] | Needed |
## UI Screens
| # | Screen Name | Description | Source | Status |
|---|-------------|-------------|--------|--------|
| 1 | Main Menu | [description] | [source] | Needed |
## HUD Elements
| # | Element | Description | Source | Status |
|---|---------|-------------|--------|--------|
## Audio
| # | Name | Type (SFX / Music / Ambient) | Description | Source | Status |
|---|------|------------------------------|-------------|--------|--------|
After writing, tell the user:
"Entity inventory saved. Next steps:
- Run
/ux-design [screen name]for each UI screen in the inventory- Run
/asset-spec system:[name],level:[name]orcharacter:[name]for each visual entity — whichever of the three the entity belongs to- Or run
/asset-specagain to work through the inventory one item at a time"
Phase 0: Parse Arguments
Extract:
- Target type:
system,level, orcharacter - Target name: the name after the colon (normalize to kebab-case)
- Review mode:
--review [full|lean|solo]if present
The effective mode is the one already resolved at the top of this skill via
resolve_config --keys review_mode, which applies the full chain; with nothing
set it follows modes.rigor — solo at minimal (the default), lean at
standard, full at full. A --review argument overrides it for this
run only.
Mode behavior:
full: spawn bothart-directorandtechnical-artistin parallellean: spawnart-directoronly — faster, skips technical constraint passsolo: no agent spawning — main session writes specs from art bible rules alone. Use for simple asset categories or when speed matters more than depth.
Phase 1: Gather Context
Read all source material before asking the user anything.
Required reads:
-
Art bible: Read
design/art/art-bible.md— fail if missing:"No art bible found. Run
/art-biblefirst — asset specs are anchored to the art bible's visual rules and asset standards."Exception — the minimal path. If there is no art bible but
design/game-brief.mdexists (atrigor: minimalno art bible is required), do not fail: anchor the specs in the brief's Art & audio direction line, and say so at the top of the output — "Anchored to the brief's one-line art direction; there is no art bible, so colour, shape and asset-standard rules below are proposals, not constraints." Offer/art-bibleonce, as optional. The written spec follows the same anchor: its header reads> **Art direction**: design/game-brief.md (Art & audio direction) — no art biblein place of the> **Art Bible**:line, each asset carries**Brief anchor:** [the brief line applied]in place of the Art Bible Anchors block, and no spec cites an Art Bible section or §8 tier. Extract: Visual Identity Statement, Color System (semantic colors), Shape Language, Asset Standards (art bible Section 8 — dimensions, formats, polycount budgets, texture resolution tiers). -
Project config: Read
performance.*andnaming.*fromproject.yaml; for any key absent or empty (including whenproject.yamlhas noperformanceornamingblock), fall back to.claude/docs/technical-preferences.md. Extract performance budgets and naming conventions.
Source doc reads (by target type):
- system: Read
design/gdd/[target-name].md. Extract the Visual/Audio Requirements section. If it doesn't exist or reads[To be designed]:"The Visual/Audio section of
design/gdd/[target-name].mdis empty. Either run/design-system [target-name]to complete the GDD, or describe the visual needs manually." UseAskUserQuestion:[A] Describe needs manually/[B] Stop — complete the GDD first - level: Read
design/levels/[target-name].md. Extract art requirements, asset list, VFX needs, and the art-director's production concept specs from Step 4. - character or entity: Read
design/narrative/characters/[target-name].mdor searchdesign/narrative/anddesign/assets/entity-inventory.mdfor a matching entry. Extract visual description, role, and any specified distinguishing features.- If no source doc exists: do not fail. Instead, use
AskUserQuestion:- Prompt: "No profile found for [name]. Describe it briefly — a sentence or two is enough."
- Options:
[A] Describe it now/[B] Skip this entity/[C] Stop here - If [A]: the user's description becomes the source. Brief answers produce concise specs; detailed answers produce detailed specs. Accept whatever level of detail the user provides and work from it.
- If no source doc exists: do not fail. Instead, use
Optional reads:
- This target's existing spec: if
design/assets/specs/[target-name]-assets.mdexists, read it — this is a re-run, and Phase 2 proposes only what is new or changed since (Phase 5 updates the file in place). - Existing manifest: Read
design/assets/asset-manifest.mdif it exists — extract already-specced assets for this target to avoid duplicates. - Related specs: Glob
design/assets/specs/*.md— scan for assets that could be shared (e.g., a common UI element specced for one system might apply here too).
Present context summary:
Asset Spec: [Target Type] — [Target Name]
- Source doc: [path] — [N] asset types identified
- Art bible: found — Asset Standards at Section 8
- Existing specs for this target: [N already specced / none]
- Shared assets found in other specs: [list or "none"]
Phase 2: Asset Identification
From the source doc, extract every asset type mentioned — explicit and implied.
For systems: look for VFX events, sprite references, UI elements, audio triggers, particle effects, icon needs, and any "visual feedback" language.
For levels: look for unique environment props, atmospheric VFX, lighting setups, ambient audio, skybox/background, and any area-specific materials.
For characters: look for sprite sheets (idle, walk, attack, death), portrait/avatar, VFX attached to abilities, UI representation (icon, health bar skin).
Group assets into categories:
- Sprite / 2D Art — character sprites, UI icons, tile sheets
- VFX / Particles — hit effects, ambient particles, screen effects
- Environment — props, tiles, backgrounds, skyboxes
- UI — HUD elements, menu art, fonts (if custom)
- Audio — SFX, music tracks, ambient loops (note: audio specs are descriptions only — no generation prompts)
- 3D Assets — meshes, materials (if applicable per engine)
Present the full identified list to the user. Use AskUserQuestion:
- Prompt: "I identified [N] assets across [N] categories for [target]. Review before speccing:"
- Show the grouped list in conversation text first
- Options:
[A] Proceed — spec all of these/[B] Remove some assets/[C] Add assets I didn't catch/[D] Adjust categories
Do NOT proceed to Phase 3 without user confirmation of the asset list.
Phase 3: Spec Generation
Spawn specialist agents based on review mode. Issue all Agent calls simultaneously — do not wait for one before starting the next.
Full mode — spawn in parallel:
art-director via Agent:
- Provide: full asset list from Phase 2, art bible Visual Identity Statement, Color System, Shape Language, the source doc's visual requirements, and any reference games/art mentioned in the art bible Section 9
- Ask: "For each asset in this list, produce: (1) a 2–3 sentence visual description anchored to the art bible's shape language and color system — be specific enough that two different artists would produce consistent results; (2) a generation prompt ready for use with AI image tools (Midjourney/Stable Diffusion style — include style keywords, composition, color palette anchors, negative prompts); (3) which art bible rules directly govern this asset (cite by section). For audio assets, describe the sonic character instead of a generation prompt."
technical-artist via Agent:
- Provide: full asset list, art bible Asset Standards (Section 8), performance budgets (
performance.*fromproject.yaml, elsetechnical-preferences.md), engine name and version - Ask: "For each asset in this list, specify: (1) exact dimensions or polycount (match the art bible Asset Standards tiers — do not invent new sizes); (2) file format and export settings; (3) naming convention (
naming.*fromproject.yaml, elsetechnical-preferences.md); (4) any engine-specific constraints this asset type must respect; (5) LOD requirements if applicable. Flag any asset type where the art bible's preferred standard conflicts with the engine's constraints."
Lean mode — spawn art-director only (skip technical-artist).
Solo mode — skip both. Derive specs from art bible rules alone, noting that technical constraints were not validated.
Announce every skipped agent by name in the output, before the specs: "technical-artist skipped — Lean mode: technical constraints not validated." / "art-director and technical-artist skipped — Solo mode: specs derived in this session; technical constraints not validated." A spec drafted without an agent must not read like one an agent reviewed.
Collect both responses before Phase 4. If any conflict exists between art-director and technical-artist (e.g., art-director specifies 4K textures but technical-artist flags the engine budget requires 512px), surface it explicitly — do NOT silently resolve.
Phase 4: Compile and Review
Combine the agent outputs into a draft spec per asset. Present all specs in conversation text using this format:
## ASSET-[NNN] — [Asset Name]
| Field | Value |
|-------|-------|
| Category | [Sprite / VFX / Environment / UI / Audio / 3D] |
| Dimensions | [e.g. 256×256px, 4-frame sprite sheet] |
| Format | [PNG / SVG / WAV / etc.] |
| Naming | [e.g. vfx_frost_hit_01.png] |
| Polycount | [if 3D — e.g. <800 tris] |
| Texture Res | [e.g. 512px — matches Art Bible §8 Tier 2] |
**Visual Description:**
[2–3 sentences. Specific enough for two artists to produce consistent results.]
**Art Bible Anchors:**
- §3 Shape Language: [relevant rule applied]
- §4 Color System: [color role — e.g. "uses Threat Blue per semantic color rules"]
**Generation Prompt:**
[Ready-to-use prompt. Include: style keywords, composition notes, color palette anchors, lighting direction, negative prompts.]
**Status:** Needed
After presenting all specs, use AskUserQuestion:
- Prompt: "Asset specs for [target] — [N] assets. Review complete?"
- Options:
[A] Approve all — write to file/[B] Revise a specific asset/[C] Regenerate with different direction
If [B]: ask which asset and what to change. Revise inline and re-present. Do NOT re-spawn agents for minor text revisions — only re-spawn if the visual direction itself needs to change.
If [C]: ask what direction to change. Re-spawn the relevant agent with the updated brief.
Phase 5: Write Spec File
After approval, ask: "May I write the spec to design/assets/specs/[target-name]-assets.md?"
If that file already exists (a re-run for the same target), update it in
place — never overwrite it wholesale. Keep its existing ASSET-NNN blocks and
IDs, apply only the changes the user approved, and append new assets with the
next project-wide IDs. Show what changes, then ask "May I update
design/assets/specs/[target-name]-assets.md?" instead of "May I write".
Write the file with:
# Asset Specs — [Target Type]: [Target Name]
> **Source**: [path to source GDD/level/character doc]
> **Art Bible**: design/art/art-bible.md
> **Generated**: [date]
> **Status**: [N] assets specced / [N] approved / [N] in production / [N] done
[all asset specs in ASSET-NNN format]
Then update design/assets/asset-manifest.md. If it doesn't exist, create it:
# Asset Manifest
> Last updated: [date]
## Progress Summary
| Total | Needed | In Progress | Done | Approved |
|-------|--------|-------------|------|----------|
| [N] | [N] | [N] | [N] | [N] |
## Assets by Context
### [Target Type]: [Target Name]
| Asset ID | Name | Category | Status | Spec File |
|----------|------|----------|--------|-----------|
| ASSET-001 | [name] | [category] | Needed | design/assets/specs/[target]-assets.md |
If the manifest already exists, append the new context block — on a re-run for this target, add the new rows to its existing block instead of appending a second one — and update the Progress Summary counts.
Ask: "May I update design/assets/asset-manifest.md?"
Phase 6: Close
Use AskUserQuestion:
- Prompt: "Asset specs complete for [target]. What's next?"
- Options:
[A] Spec another system — /asset-spec system:[next-system][B] Spec a level — /asset-spec level:[level-name][C] Spec a character — /asset-spec character:[character-name][D] Run /asset-audit — validate delivered assets against specs[E] Stop here
Asset ID Assignment
Asset IDs are assigned sequentially across the entire project — not per-context. Read the manifest before assigning IDs to find the current highest number:
Grep pattern="ASSET-" path="design/assets/asset-manifest.md"
Start new assets from ASSET-[highest + 1]. This ensures IDs are stable and unique across the whole project.
If no manifest exists yet, start from ASSET-001.
Shared Asset Protocol
Before speccing an asset, check if an equivalent already exists in another context's spec:
- Common UI elements (health bars, score displays) are often shared across systems
- Generic environment props may appear in multiple levels
- Character VFX (hit sparks, death effects) may reuse a base spec with color variants
If a match is found: reference the existing ASSET-ID rather than creating a duplicate. Note the shared usage in the manifest's referenced-by column.
"ASSET-012 (Generic Hit Spark) already specced for Combat system. Reusing for Tower Defense — adding tower-defense to referenced-by."
Error Recovery Protocol
If any spawned agent returns BLOCKED or cannot complete:
- Surface immediately: "[AgentName]: BLOCKED — [reason]"
- In
leanmode or iftechnical-artistblocks: proceed with art-director output only — note that technical constraints were not validated - In
solomode or ifart-directorblocks: derive descriptions from art bible rules — flag as "Art director not consulted — verify against art bible before production" - Always produce a partial spec — never discard work because one agent blocked
Collaborative Protocol
Applies in collaborative mode (the default). For guided and
autonomous modes, see .claude/docs/automation-modes.md — the rules below
describe what collaborative mode requires, not universal behavior.
Every phase follows: Identify → Confirm → Generate → Review → Approve → Write
- Never spec assets without first confirming the asset list with the user
- Always anchor specs to the art bible — a spec that contradicts the art bible is wrong
- Surface all agent disagreements — do not silently pick one
- Write the spec file only after explicit approval
- Update the manifest immediately after writing the spec
Recommended Next Steps
- Run
/asset-spec [next-context]to continue speccing remaining systems, levels, or characters - Run
/asset-auditto validate delivered assets against the written specs and identify gaps or mismatches
How can the creator link this skill?
Add the canonical catalog link to the repository README so users can inspect current installs and available audits. The publishing guide covers the complete discovery path.
<a href="https://skillzs.dev/skills/donchitos/claude-code-game-studios/asset-spec">View asset-spec on skillZs</a>