Unity Package Agent Skill

Package Skills

Manage installed Unity packages and package-related helper flows such as Cinemachine and Splines setup.

Guardrails

Operating Mode (v1.9 three-tier):

• Approval (default): query skills (package_list, package_check, package_search, package_get_dependencies, package_get_versions, package_get_cinemachine_status) run directly. Mutators (package_install, package_remove, package_install_cinemachine, package_install_splines, package_refresh) are FullAuto — on MODE_RESTRICTED, run the grant protocol.
• Auto / Bypass: SemiAuto and FullAuto run directly.
• Auto-forbidden in this module: package_install and package_remove (MayTriggerReload = true, RiskLevel = "high"; package_remove also carries SkillOperation.Delete). They are reachable only under Bypass mode or via a user-managed Allowlist entry; the grant flow returns MODE_FORBIDDEN.
• Install/remove/refresh jobs return immediately with a jobId; the actual package import + Domain Reload happens asynchronously and may make the REST server transiently unavailable. Poll with job_status / job_wait.

DO NOT (common hallucinations):

• package_add / package_update do not exist -> use package_install
• package_get_info does not exist -> use package_list, package_check, package_get_dependencies, or package_get_versions
• package_search searches the installed package cache only; it does not query the Unity Registry
• Package query skills initialize their cache automatically after Domain Reload. During the short cold-start window they return { success: false, status: "refreshing", cacheReady: false, retryStrategy: "wait_and_retry", retryAfterSeconds: 2 }; retry instead of treating this as installed=false.
• Package install/remove/refresh jobs can trigger package import and Domain Reload; expect transient server unavailability and use returned job IDs

Routing:

• For Cinemachine quick setup -> use package_install_cinemachine
• For Splines quick setup -> use package_install_splines
• For project manifest inspection -> use project_get_packages
• For define symbol changes after package installation -> use debug_set_defines

Skills

package_list

List all installed packages currently cached by UnitySkills.

Parameters: None.

Returns: { success, count, packages }

package_check

Check whether a package is installed.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| packageId | string | Yes | - | Package ID such as com.unity.cinemachine |

Returns: { packageId, installed, version }

package_install

Install a package. Returns an async job when the request is accepted.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| packageId | string | Yes | - | Package ID to install |

| version | string | No | null | Optional explicit version |

Returns: { success, status, jobId, message, serverAvailability }

package_remove

Remove an installed package. Returns an async job when the request is accepted.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| packageId | string | Yes | - | Installed package ID to remove |

Returns: { success, status, jobId, message, serverAvailability }

package_refresh

Refresh the installed package cache used by query skills.

Parameters: None.

Returns: { success, status, jobId, message }

package_install_cinemachine

Install Cinemachine using the supported package/version strategy.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| version | int | No | 3 | 2 for CM2, 3 for CM3 |

Notes:

• CM3 auto-installs the Splines dependency.
• If the requested line is already installed, this skill can return immediate success instead of a job.

Returns: { success, status?, jobId?, message, serverAvailability? }

package_install_splines

Install or upgrade Unity Splines using the recommended version for the current Unity editor line.

Parameters: None.

Returns: { success, status?, jobId?, message, serverAvailability? }

package_get_cinemachine_status

Get current Cinemachine and Splines installation status.

Parameters: None.

Returns: { cinemachine, splines }

package_search

Search the installed package cache by package name or display name.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| query | string | Yes | - | Search keyword |

Returns: { success, query, count, packages }

package_get_dependencies

Get dependency information for one installed package.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| packageId | string | Yes | - | Installed package ID |

Returns: { success, packageId, version, dependencyCount, dependencies }

package_get_versions

Get available versions for one installed package.

| Parameter | Type | Required | Default | Description |

|-----------|------|----------|---------|-------------|

| packageId | string | Yes | - | Installed package ID |

Returns: { success, packageId, currentVersion, compatibleVersion, latestVersion, allVersions }

Exact Signatures

Exact names, parameters, defaults, and returns are defined by GET /skills/schema or unity_skills.get_skill_schema(), not by this file.