g-skl-plugins

---

name: g-skl-plugins maturity: beta description: Authoritative reference for the gald3r plugin system — install, remove, update, list, scaffold, and compatibility-check third-party plugins that bundle skills/commands/agents/rules/hooks. Documents the gald3r-plugin.yaml manifest, registry.json, the installed.yaml ledger, and the plugin_source: provenance convention (ADR-015 / SS-007). Single source of truth for everything plugin-related. token_budget: medium subsystem_memberships: [PLUGIN_SYSTEM]

g-skl-plugins — gald3r plugin system reference

Plays the role for the plugin lifecycle that g-skl-tasks plays for tasks: the one place an agent reads to understand how plugins are installed, removed, updated, listed, authored, and checked for compatibility.

Design source of truth: ADR-015 (maintainer-tree ADR — not shipped in installs; T1652 D4) and subsystem SS-007 (.gald3r/subsystems/plugin_system.md). Read those for the why; this skill is the operational how.

Activate for: install a plugin, remove/uninstall a plugin, update plugins, list installed/available plugins, scaffold a new plugin, check plugin compatibility with the host, author a third-party plugin, or any @g-plugin-* operation.

---

⚠️ Implementation-state honesty (read this first)

The plugin system was designed in full (ADR-015) and the lifecycle is now a first-class engine surface (T663, epic T541): all six ops live in gald3r.systems.plugins.PluginSystem and are reachable via the gald3r plugin … CLI and the gald3r_plugin_* MCP tools — one implementation, no PowerShell. The retired PowerShell scripts (BUG-128/129/130) are not the source of truth; prefer the engine ops.

Operation	Engine op (CLI)	MCP tool	State
INSTALL	gald3r plugin install <local-source> [--dry-run]	gald3r_plugin_install	✅ Engine (T663)
REMOVE	gald3r plugin remove <id> (alias uninstall) [--dry-run]	gald3r_plugin_remove	✅ Engine (T663)
LIST	gald3r plugin list	gald3r_plugin_list	✅ Engine (T663)
NEW	gald3r plugin new <id> [--name --author --subsystem]	gald3r_plugin_new	✅ Engine (T663)
CHECK_COMPAT	gald3r plugin check-compat <local-source>	gald3r_plugin_check_compat	✅ Engine (T663)
UPDATE	gald3r plugin update <id> [--source --force --dry-run]	gald3r_plugin_update	✅ Engine (T663)

The engine owns the manifest schema, the installed.yaml ledger, the registry config, the compat floor (gald3r_min_version ≤ .gald3r_sys/VERSION), the D6 conflict-abort (never overwrites a non-plugin core component), and the plugin_source: provenance stamping that makes safe removal possible — a single source reused by every op.

Source resolution: the engine installs from a local path / vendored .gald3r_sys/plugins/<id>/ dir (a remote https:// source is rejected, matching the engine's no-daemon / single-GET discipline — vendor the plugin dir first). Lifecycle scripts (install.ps1 / uninstall.ps1 / upgrade.ps1) are data-declared but never auto-run by the engine (ADR-015 D7) — inspect and run them yourself if you opt in.

The legacy @g-plugin-* command names and the retired .gald3r_sys/plugins/scripts/*.ps1 remain documented below for historical context; the engine ops above are the live path.

---

Concepts

A plugin is a self-contained, versioned directory that bundles any subset of gald3r's five component types plus one declarative manifest. It is additive: it copies components into the canonical component dirs and never overwrites gald3r-core components (conflict = abort, ADR-015 D6).

.gald3r_sys/plugins/<plugin-id>/
├── gald3r-plugin.yaml      # manifest (data-only, REQUIRED)
├── CHANGELOG.md            # version history (used for update excerpts)
├── skills/<name>/SKILL.md  # folder-per-skill
├── commands/*.md
├── agents/*.md
├── rules/*.md
├── hooks/*.ps1
├── install.ps1             # optional, opt-in lifecycle script
├── uninstall.ps1           # optional, opt-in lifecycle script
└── upgrade.ps1             # optional, opt-in lifecycle script

Component mapping (plugin subdir → canonical target; skills is folder-per-skill, the rest are flat files):

Plugin subdir	Copied to	Type
skills/<name>/SKILL.md	.gald3r_sys/skills/<name>/	skill
commands/*.md	.gald3r_sys/commands/	command
agents/*.md	.gald3r_sys/agents/	agent
rules/*.md	.gald3r_sys/rules/	rule
hooks/*.ps1	.gald3r_sys/hooks/	hook
gald3r-plugin.yaml	stays at plugin root	manifest
install.ps1 / uninstall.ps1 / upgrade.ps1	stays; opt-in run	lifecycle script

Key state files:

File	Role
.gald3r_sys/plugins/<id>/	versioned, inspectable plugin source
.gald3r_sys/plugins/installed.yaml	install ledger (record of truth for removal/update)
.gald3r_sys/plugins/.backup/<id>-<version>/	pre-update backups (≤3 retained per plugin)
.gald3r_sys/config/plugins.yaml	host config; registry_url: override
.gald3r/config/plugins/<id>.yaml	per-plugin, project-local config (gitignorable)
.gald3r/logs/plugin_update_failures.log	append-only update-failure audit
registry registry.json	GitHub-hosted catalog of available plugins (raw HTTPS)

Default registry: https://raw.githubusercontent.com/gald3r/plugin-registry/main/registry.json (override via plugins.yaml registry_url: or -RegistryUrl).

---

Agent decision tree

Need to work with a plugin?
│
├─ Add a new plugin to the project ──────────────► INSTALL  (@g-plugin-install)        (planned here)
├─ Get newer versions of installed plugins ──────► UPDATE   (@g-plugin-update)         ✅ available
├─ See what's installed / available ─────────────► LIST     (@g-plugin-list)           (planned here)
├─ Take a plugin out cleanly ────────────────────► REMOVE   (@g-plugin-remove)         (planned here)
├─ Author / start a brand-new plugin ────────────► NEW      (@g-plugin-new)            (planned here)
└─ Will plugin X run on this host? ──────────────► CHECK_COMPAT (validate_plugin_manifest.ps1)  (planned here)

Before invoking any non-UPDATE operation, confirm its script exists:

Test-Path .gald3r_sys/plugins/scripts/install_plugin.ps1   # etc.

If absent, do not fabricate the behavior — tell the user the operation is designed (ADR-015) but not yet implemented in this install, and stop.

---

OPERATIONS

UPDATE — @g-plugin-update <id> ✅ implemented (engine, T663 / T1601)

When: an installed plugin's local source has a newer version, or you need to re-apply a plugin (--force). Backed by gald3r.systems.plugins.PluginSystem.update — the Python successor to the historical update_plugin.ps1 (retired T1601, PS1-KILL epic T667).

Invoke (from project root):

uv run --project .gald3r_sys/engine gald3r plugin update <id> [--source <path>] [--dry-run] [--force]

Flag	Effect
<id>	Required. Update this one installed plugin.
--source <path>	Explicit local source dir (default: the already-vendored .gald3r_sys/plugins/<id>/)
--dry-run	Return the planned from_version -> to_version + component inventory; apply nothing
--force	Re-install even if already at the source version

Flow: look up installed.yaml entry → resolve source + read its manifest → compat check (gald3r_min_version) → compare versions (same + no --force -> up_to_date, stop) → (--dry-run stops here) → apply via the same path as plugin install (remove stale components, copy new, rewrite ledger). Returns {ok, status, id, from_version, to_version, components, reasons, dry_run}.

Scope narrowing from the historical .ps1 (T1601): this is single-plugin, local-source only — no bulk "check every installed plugin against a remote HTTPS registry" loop, no CHANGELOG excerpt, no interactive confirm prompts, no upgrade.ps1 lifecycle execution, and no versioned on-disk backup/rollback directory. These were designed-but-not-carried-forward when the engine module absorbed this op, matching INSTALL/REMOVE/LIST/NEW/CHECK_COMPAT below (also "designed but never ported"). Remote https:// registry sources are intentionally not fetched by this engine surface — use --source <local-path> for anything not already vendored under .gald3r_sys/plugins/.

---

INSTALL — @g-plugin-install <id> (planned here)

When: add a plugin to the project for the first time. ADR-015 contract:

.gald3r_sys/plugins/scripts/install_plugin.ps1 -Source <local-path|github-url> [-Version <semver>] [-RunInstallScript] [-DryRun]

• Fetch from a local path or GitHub URL (GitHub-URL path designed; local-path path is what was network-tested in the source repo).
• Validate gald3r-plugin.yaml; enforce gald3r_min_version host floor.
• Conflict-abort (D6): refuses to overwrite any gald3r-core component.
• Copy components into canonical dirs; stamp each with plugin_source: <id> frontmatter.
• Record the installed.yaml ledger entry.
• Never auto-runs lifecycle scripts (D7): install.ps1 runs only with opt-in -RunInstallScript, after printing a preview.

REMOVE — @g-plugin-remove <id> (alias @g-plugin-uninstall) (planned here)

When: cleanly uninstall a plugin. ADR-015 contract (remove_plugin.ps1):

.gald3r_sys/plugins/scripts/remove_plugin.ps1 -PluginId <id> [-Force] [-DryRun] [-KeepConfig] [-RunUninstallScript]

• Uses installed.yaml as the record of truth (D4); removes exactly the listed component files — but only those still carrying this plugin's plugin_source: provenance, so gald3r-core and other plugins' files are never touched (D6).
• Preserves components modified after install unless -Force.
• Runs uninstall.ps1 only with opt-in -RunUninstallScript, after a preview (D7).
• -KeepConfig retains .gald3r/config/plugins/<id>.yaml. Idempotent (removing an absent plugin is a no-op); warns on dangling cross-plugin references (cascade check).

LIST — @g-plugin-list (planned here)

When: see installed plugins (installed.yaml) and/or available plugins (registry.json). Reads ledger + registry; reports id, installed version, latest version, and components.

NEW — @g-plugin-new <id> (planned here)

When: scaffold a skeleton to author a new plugin — creates .gald3r_sys/plugins/<id>/ with a starter gald3r-plugin.yaml, empty component subdirs, a CHANGELOG, and optional lifecycle-script stubs. See the third-party development guide below for the manifest the scaffolder produces.

CHECK_COMPAT — validate_plugin_manifest.ps1 (planned here)

When: validate a plugin's manifest and check host compatibility before install/update. ADR-015 contract:

.gald3r_sys/plugins/scripts/validate_plugin_manifest.ps1 -PluginDir <path>   # exit 0 = valid

Checks the manifest is present and well-formed (at minimum id + version), and that gald3r_min_version ≤ the host's .gald3r_sys/VERSION (SemVer compare). The engine's plugin update op (see UPDATE above) calls the equivalent PluginSystem.check_compat internally.

---

Manifest format — gald3r-plugin.yaml

Data-only YAML (no inline code), at the plugin root. Example:

# gald3r-plugin.yaml
id: gald3r-git-toolkit          # REQUIRED — unique, kebab-case, matches dir + ledger key
version: 1.2.0                  # REQUIRED — SemVer
name: Git Toolkit               # human-readable
description: Extra git automation commands and a pre-push hook.
author: jane-doe
homepage: https://github.com/jane-doe/gald3r-git-toolkit
license: MIT
gald3r_min_version: 1.8.0       # host floor — refuse install/update below this
default_subsystem: PLATFORM_INTEGRATION   # inherited by components omitting their own tag
components:                     # what this plugin ships (mirrors the subdirs)
  commands:
    - g-git-sync.md
  hooks:
    - g-git-sync-hook.ps1
  skills:
    - skl-git-helper
lifecycle:                      # all optional, all opt-in, never auto-run
  install: install.ps1
  uninstall: uninstall.ps1
  upgrade: upgrade.ps1

Rules:

• id + version are the only hard-required fields (matches the validator's minimal check).
• id must match the plugin directory name and the installed.yaml ledger key.
• Manifests are data-only — no executable logic. Behavior lives in the opt-in install.ps1 / uninstall.ps1 / upgrade.ps1 lifecycle scripts.
• Every copied component MUST carry subsystem_memberships: (g-rl-38). If a component file omits it, it inherits default_subsystem from the manifest.

Registry format — registry.json

GitHub-hosted catalog format (ADR-015 design). Not fetched by the current engine surface (T1601): gald3r plugin update/install/check-compat operate on local source paths only and intentionally do not download from a remote https:// registry — see the UPDATE section's scope-narrowing note above. registry_url: in .gald3r_sys/config/plugins.yaml is still read (gald3r plugin list reports it) but is not dereferenced over HTTP by this tree. Accepted shape (when a registry consumer is added): both { "plugins": { ... } } and a bare top-level map.

{
  "plugins": {
    "gald3r-git-toolkit": {
      "version": "1.2.0",
      "source": "https://github.com/jane-doe/gald3r-git-toolkit",
      "gald3r_min_version": "1.8.0",
      "description": "Extra git automation commands and a pre-push hook."
    },
    "gald3r-3d-pack": {
      "version": "0.4.1",
      "source": "https://github.com/acme/gald3r-3d-pack",
      "gald3r_min_version": "1.9.0"
    }
  }
}

• version (string, SemVer) and source drive the update plan; gald3r_min_version is the compatibility floor; description is informational.
• source may be an https:// URL (needs the installer's download helper) or a local path (a versioned subdir <source>/<version>/ or the dir itself — used for fixtures and vendored sources; this is the path that works on the current tree).
• Override the URL via plugins.yaml registry_url: or the -RegistryUrl flag; a local file path is also accepted (test fixtures).

Install ledger — installed.yaml

Written/read by the lifecycle scripts; the record of truth for removal and update. Shape:

# gald3r plugin install ledger (installed.yaml) -- ADR-015
plugins:
  gald3r-git-toolkit:
    version: 1.2.0
    source: https://github.com/jane-doe/gald3r-git-toolkit
    installed_at: 2026-05-01T00:00:00Z
    components:
      commands: [g-git-sync.md]
      hooks: [g-git-sync-hook.ps1]

plugin_source: tagging convention

Every component a plugin copies into a canonical dir is stamped with a plugin_source: field in its frontmatter (markdown) or header comment (PowerShell), naming the owning plugin id. This provenance tag is what makes safe removal possible:

---
subsystem_memberships: [PLATFORM_INTEGRATION]
plugin_source: gald3r-git-toolkit
---

# g-git-sync-hook.ps1
# @subsystems: PLATFORM_INTEGRATION
# plugin_source: gald3r-git-toolkit

• REMOVE deletes only files that still carry the matching plugin_source:, so gald3r-core files (no tag) and other plugins' files are never touched.
• It also enables deterministic re-materialization after parity sync (-SyncGaldSys) overwrites the canonical dirs (depends on SS-004 parity-pipeline).

---

What NOT to do

❌ Don't	✅ Do instead	Why
Manually edit a plugin-installed file in .gald3r_sys/commands/ etc.	Edit the plugin source in .gald3r_sys/plugins/<id>/ and re-run @g-plugin-update (or update upstream)	Hand-edits are silently lost on the next update/re-materialize, and post-install modifications get preserve-skipped on REMOVE
Manually Remove-Item plugin component files	Use @g-plugin-remove <id>	Leaves a stale installed.yaml ledger entry and dangling cross-plugin references
Install from an untrusted source without inspecting it	Read the plugin's install.ps1 / uninstall.ps1 / upgrade.ps1 before opting in with -RunInstallScript etc.	Lifecycle scripts execute arbitrary code; ADR-015 makes them opt-in + preview-first precisely so you review them
Run @g-plugin-update --no-backup casually	Keep backups on; use --no-backup only when you understand rollback is disabled	A mid-update failure with no backup can leave the install in a broken half-applied state
Let a plugin overwrite a gald3r-core component	Resolve the conflict upstream; install aborts on conflict by design	Plugins are additive only (D6); silently shadowing core breaks the framework
Invoke a @g-plugin-* command whose script is absent on this tree	Check Test-Path first; report it as designed-but-not-implemented	Fabricating behavior for a missing script misleads the user

---

Third-party plugin development guide

To author a plugin others can install:

1. Scaffold the directory: .gald3r_sys/plugins/<plugin-id>/ (use @g-plugin-new when present, or create it by hand).

2. Write gald3r-plugin.yaml with at least id + version; add name, description, author, license, homepage, gald3r_min_version, default_subsystem, components, and (optional) lifecycle.

3. Add component files under the matching subdirs, following gald3r naming conventions:

   Component	Subdir	Naming convention
   Skill	skills/<name>/SKILL.md	folder-per-skill; folder skl-<topic> or g-skl-<topic>; SKILL.md with frontmatter (name, description, subsystem_memberships, optional skill_trust_level)
   Command	commands/*.md	g-<verb>-<noun>.md (kebab-case), frontmatter with subsystem_memberships:
   Agent	agents/*.md	g-agnt-<role>.md, frontmatter with subsystem_memberships:
   Rule	rules/*.md	g-rl-NN-<topic>.md, frontmatter with subsystem_memberships:
   Hook	hooks/*.ps1	g-hk-<name>.ps1, # @subsystems: comment in first 15 lines

4. Tag every component with subsystem_memberships: (g-rl-38) and — once installed — plugin_source: <plugin-id> (the installer stamps this; author files may pre-declare it).

5. Keep manifests data-only. Any real work goes in opt-in install.ps1 / uninstall.ps1 / upgrade.ps1. Make them ASCII-safe and PS 5.1 + PS 7 compatible; accept -ProjectRoot, and for upgrade.ps1 also -FromVersion / -ToVersion.

6. Maintain CHANGELOG.md with ## [x.y.z] headers — @g-plugin-update shows the excerpt between the installed and new version.

7. Version with SemVer and set gald3r_min_version to the lowest host you support.

8. Publish by adding an entry to a registry.json (your own or the gald3r registry) with version, source, and gald3r_min_version.

Trust note (mirrors skl-skill-create / C-032): contributed skills may declare a skill_trust_level: of core / local / community. community or unset surfaces a non-blocking provenance warning at install time — installers should inspect community plugin bodies before first invocation.

---

Related

• g-skill-pack-add / -del / -list / -save — the skill-pack system (.gald3r_sys/skill_packs/<pack>/) is a separate, curated bundle-of-skills mechanism, not the third-party plugin system documented here. Don't conflate them.
• SS-007 plugin_system.md — subsystem spec (decisions, scope boundary, constraints).
• ADR-015 — foundational architecture decisions (D1–D7 referenced throughout; maintainer-tree ADR, not shipped).
• g-rl-38 component-creation-standards — mandatory subsystem_memberships: tagging that plugin components must satisfy.