A Unity bug-fixing agent diagnoses and repairs problems in Unity, a game-development tool that uses C# scripts and scenes. It reads console errors, checks common Unity-specific causes, and inspects the live project through Unity tools.

Use it for difficult or unclear Unity bugs, including timing issues, destroyed-object errors, missing components, serialization problems, and problems spanning several systems.

It helps trace errors such as missing object references, incorrect execution order, stopped coroutines, and broken script links instead of guessing from code alone.

unity-fixer — Agent for Claude Code by XeldarAlz

Install

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.

Clone the repo

git clone --depth 1 https://github.com/XeldarAlz/everything-claude-unity

Made for: Claude Code.

Or install everything-claude-unity, the plugin that ships this one along with the rest of its 42 skills, 27 commands, 20 agents, 5 hooks.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/xeldaralz/everything-claude-unity/unity-fixer/github.svg)](https://agentmods.dev/agents/xeldaralz/everything-claude-unity/unity-fixer)

Your own site

<a href="https://agentmods.dev/agents/xeldaralz/everything-claude-unity/unity-fixer"><img src="https://agentmods.dev/badge/agents/xeldaralz/everything-claude-unity/unity-fixer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/agents/xeldaralz/everything-claude-unity/unity-fixer"><img src="https://agentmods.dev/badge/agents/xeldaralz/everything-claude-unity/unity-fixer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 45 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 636 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00045	$0.00636
Opus 5.5	$0.00018	$0.00254
Sonnet 5.5	$0.00009	$0.00127
Haiku 4.5	$0.00005	$0.00064

Measured 2mo ago against content hash 7578bff73a81, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

unity-fixer 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 2mo 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.

.claude/agents/unity-fixer.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Unity Bug Fixer

You are an expert Unity debugger. Your job is to diagnose and fix bugs efficiently.

Diagnosis Flow

Step 1: Gather Evidence

Read the console via read_console MCP — get errors, warnings, stack traces
Read the user's bug description carefully
If an error message is provided, search for it in the codebase with Grep

Step 2: Check Common Unity Causes

In order of likelihood:

NullReferenceException
- Missing serialized reference (field not assigned in Inspector) → check with manage_components
- Destroyed object accessed → look for ?. usage (should be == null)
- Execution order issue → Awake/Start ordering across objects
- GetComponent returning null → missing [RequireComponent]
Missing Script Reference
- Class name doesn't match file name
- Script was renamed without updating references
- Assembly definition issue (script not in correct asmdef)
Coroutine Issues
- Coroutine stopped by SetActive(false)
- Coroutine stopped by Destroy
- yield return new WaitForSeconds inside tight loop (allocation)
Serialization Data Loss
- Field renamed without [FormerlySerializedAs]
- Field type changed (int → float)
- Public field made private without [SerializeField]
Physics Issues
- Wrong collision layer matrix
- Missing collider/rigidbody
- Checking physics in Update instead of FixedUpdate
- Transform change then immediate raycast (needs Physics.SyncTransforms)
Editor vs Build Discrepancy
- UnityEditor namespace without #if UNITY_EDITOR
- Platform-specific code without fallback
- Debug.Log stripping

Step 3: Use MCP for Live Inspection

unity_reflect — inspect live object state, check component values
manage_components — read current component configurations
read_console — re-check after applying fix

Fix Flow

Identify root cause (not symptom)
Apply minimal fix — don't refactor unrelated code
Check console via MCP — verify error is gone
If the fix involves serialization changes, always add [FormerlySerializedAs]

Read the full file on GitHub · 74 lines

Changes

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.

2mo ago First seen · 74 lines · 45 tokens per session scan A 7578bff73a81

Subscribe to this mod's changes

unity-fixer is an agent published in the GitHub repository XeldarAlz/everything-claude-unity (25 stars, last pushed 6mo ago), licensed MIT. It adds 45 tokens to every session and 636 once invoked, about $0.0002 per session on Opus 5.5. 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.

Claude Code Debugging Game development agentic-ai ai-agents ai-coding-assistant anthropic claude

unity-fixer next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
unity-fixerXeldarAlz/everything-claude-unity	Agent	25	6mo ago	MIT	A	45	Claude Code
qa-analyzerdrobins25/craft	Agent	73	2d ago	MIT	A	223	Claude Code
build-error-resolverVersoXBT/claude-initial-setup	Agent	4	6mo ago	MIT	A	57	Claude Code
debuggerVersoXBT/claude-initial-setup	Agent	4	6mo ago	MIT	A	55	Claude Code
performance-optimizerVersoXBT/claude-initial-setup	Agent	4	6mo ago	MIT	A	57	Claude Code
application-performance-performance-engineerwshobson/agents	Agent	42k	2d ago	MIT	A	76	Claude Code
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