Unity-MCP connects AI coding agents to the Unity game engine through MCP, letting them work with the Unity Editor and running games. It is used by game developers to generate code, automate development and testing, debug projects, and add AI-driven behavior to games. The catalogue entries provide skills, instructions, an MCP integration, and settings for operating this workflow.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add IvanMurzak/Unity-MCP --skill assets-prefab-savegit clone --depth 1 https://github.com/IvanMurzak/Unity-MCPWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ivanmurzak/unity-mcp/assets-prefab-save)<a href="https://agentmods.dev/skills/ivanmurzak/unity-mcp/assets-prefab-save"><img src="https://agentmods.dev/badge/skills/ivanmurzak/unity-mcp/assets-prefab-save.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium MCP Rug Pull · line 37 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00037 | $0.00737 |
| Opus 5 | $0.00018 | $0.00368 |
| Sonnet 5 | $0.00007 | $0.00147 |
| Haiku 4.5 | $0.00004 | $0.00074 |
Grade A, and why
assets-prefab-save scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Assets / Prefab / Save
Save a prefab. Use it when you are in prefab editing mode in Unity Editor. Use 'assets-prefab-open' tool to open a prefab first.
Behavior
Calls PrefabUtility.SaveAsPrefabAsset on the current prefab stage's contents root, clears the stage's dirtiness flag, repaints editor windows, and returns an AssetObjectRef to the saved prefab. Throws when no prefab stage is currently open.
How to Call
unity-mcp-cli run-tool assets-prefab-save --input '{
"nothing": "string_value"
}'
For complex input (multi-line strings, code), save the JSON to a file and use:
unity-mcp-cli run-tool assets-prefab-save --input-file args.jsonOr pipe via stdin (recommended):
unity-mcp-cli run-tool assets-prefab-save --input-file - <<'EOF' {"param": "value"} EOF
Troubleshooting
If unity-mcp-cli is not found, either install it globally (npm install -g unity-mcp-cli) or use npx unity-mcp-cli instead.
Read the /unity-initial-setup skill for detailed installation instructions.
Input
| Name | Type | Required | Description |
|---|---|---|---|
nothing |
string |
No |
Input JSON Schema
{
"type": "object",
"properties": {
"nothing": {
"type": "string"
}
}
}
Output
Output JSON Schema
{
"type": "object",
"properties": {
"result": {
"$ref": "#/$defs/AIGD.AssetObjectRef",
"description": "Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders."
}
},
"$defs": {
"System.Type": {
"type": "string"
},
"AIGD.AssetObjectRef": {
"type": "object",
"properties": {
"instanceID": {
"type": "integer",
"description": "instanceID of the UnityEngine.Object. If this is '0' and 'assetPath' and 'assetGuid' is not provided, empty or null, then it will be used as 'null'."
},
"assetType": {
"$ref": "#/$defs/System.Type",
"description": "Type of the asset."
},
"assetPath": {
"type": "string",
"description": "Path to the asset within the project. Starts with 'Assets/'"
},
"assetGuid": {
"type": "string",
"description": "Unique identifier for the asset."
}
},
"required": [
"instanceID"
],
"description": "Reference to UnityEngine.Object asset instance. It could be Material, ScriptableObject, Prefab, and any other Asset. Anything located in the Assets and Packages folders."
}
},
"required": [
"result"
]
}
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 8d ago First seen · 108 lines · 37 tokens per session scan A 55e1b2a7a1fe
assets-prefab-save is a skill published in the GitHub repository IvanMurzak/Unity-MCP (4,198 stars, last pushed 3d ago), licensed Apache-2.0. It adds 37 tokens to every session and 737 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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