unity-cli-exec-code

Unity CLI Exec Code (Fallback)

Execute raw C# in a running Unity Editor via the Roslyn-based CSharpConsole REPL. Always prefer the unity-cli-command skill first.

Then check the snippet library (cs snippets search <description>) before writing ad-hoc code. After solving a non-trivial task that's likely to recur, consider distilling it into a snippet — see the unity-cli-snippets skill.

Running cs: below, cs is shorthand for python "$HOME/.unity-cli-plugin/current/cli/cs.py" — one stable path, run verbatim without changing directory. If it's not installed yet, run the unity-cli-setup skill once first.

Usage

Inline code:

python "$HOME/.unity-cli-plugin/current/cli/cs.py" exec --json --project "$(pwd)" "<C# code>"

From a file (avoids shell quoting hazards for long/complex snippets):

python "$HOME/.unity-cli-plugin/current/cli/cs.py" exec --json --project "$(pwd)" --file path/to/snippet.cs

All examples below use the inline form, showing only the C# code portion for brevity.

REPL Features

This is a Roslyn REPL, not a simple eval. Non-obvious capabilities:

• Top-level syntax — no class/Main boilerplate; write statements directly
• Expression auto-return — the last expression value is returned in the result; prefer over Debug.Log
• Cross-submission state — variables, usings, and types persist across exec calls within the session
• Private member access — compiler bypasses private/protected/internal at compile time
• Pre-loaded usings — System and UnityEngine are available by default. Add using System.Linq; or using System.Collections.Generic; explicitly when needed (they persist in the session)

Patterns

Expression evaluation

DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")
// inline chains work too:
var cam = Camera.main; cam.fieldOfView

Multi-step with cross-submission state

// Call 1: store a reference
var player = GameObject.Find("Player");

// Call 2: `player` is still alive
player.transform.position

Private member access (no reflection needed)

var go = GameObject.Find("Main Camera"); go.m_InstanceID

LINQ queries over live scene

// Prefer FindObjectsByType (Unity 2023.1+); FindObjectsOfType is deprecated.
using System.Linq; UnityEngine.Object.FindObjectsByType<Rigidbody>(FindObjectsSortMode.None).Select(r => $"{r.name}: mass={r.mass}").ToList()
// System.Linq persists — no need to re-import
Resources.FindObjectsOfTypeAll<GameObject>().Where(g => !g.activeInHierarchy).Select(g => g.name).ToList()
// Resources.FindObjectsOfTypeAll is still current — it returns inactive/asset objects too.

AssetDatabase

using System.Linq; UnityEditor.AssetDatabase.FindAssets("t:Material").Select(g => UnityEditor.AssetDatabase.GUIDToAssetPath(g)).ToList()

Define reusable helpers (persists in session)

// Call 1: define a function
string Dump(Transform t, int d=0) { var s = new string(' ', d*2) + t.name; foreach(Transform c in t) s += "\n" + Dump(c, d+1); return s; }
// Call 2: use it — function persists across submissions
Dump(GameObject.Find("Canvas").transform)

Batch modify

foreach(var r in GameObject.FindGameObjectsWithTag("Debug").SelectMany(g => g.GetComponents<MeshRenderer>())) r.enabled = false;

Session Reset

Reset when variable name collisions or stale state occur:

python "$HOME/.unity-cli-plugin/current/cli/cs.py" command --json --project "$(pwd)" session reset

Notes

• Always use --json for parseable output
• Check result.ok and result.exitCode for success/failure
• Port is auto-detected from Temp/CSharpConsole/refresh_state.json