diff --git a/docs/turn-loop/config.md b/docs/turn-loop/config.md
index 116da2a1..931134d1 100644
--- a/docs/turn-loop/config.md
+++ b/docs/turn-loop/config.md
@@ -158,7 +158,7 @@ Two per-agent `agent.nix` options control this:
 
 ```nix
 hyperhive.claudeMarketplaces = [ "anthropics/claude-plugins-official" ];  # default
-hyperhive.claudePlugins = [ "formatter@my-marketplace" ];                  # default: []
+hyperhive.claudePlugins = [ "skill-creator@claude-plugins-official" ];     # default
 hyperhive.claudePluginsAutoUpdate = false;                                 # default
 ```
 
@@ -168,9 +168,17 @@ hyperhive.claudePluginsAutoUpdate = false;                                 # def
   custom marketplaces. Idempotent — re-adding an existing source is
   a no-op.
 - **`claudePlugins`** — list of plugin specs passed to
-  `claude plugin install <spec>`. Empty by default. Each spec is
-  installed on every boot (`install` is expected to be idempotent);
-  failures log a warning but do not abort boot.
+  `claude plugin install <spec>`. Each spec is installed on every boot
+  (`install` is expected to be idempotent); failures log a warning but
+  do not abort boot. Defaults to Anthropic's `skill-creator`, so every
+  agent can author, refine, and evaluate its own skills without any
+  per-agent wiring.
+
+> Both plugin lists follow ordinary NixOS list-option semantics: a
+> per-agent definition **replaces** the default, it does not extend it.
+> An agent that sets `claudePlugins` and still wants `skill-creator`
+> has to list it explicitly alongside its own entries — likewise for
+> the official marketplace in `claudeMarketplaces`.
 - **`claudePluginsAutoUpdate`** — when `true`, runs
   `claude plugin marketplace update` before installing plugins to pull
   the latest index. Disabled by default to keep boot times short and
diff --git a/nix/agent-modules/claude-settings.nix b/nix/agent-modules/claude-settings.nix
index 593a52fa..e384b960 100644
--- a/nix/agent-modules/claude-settings.nix
+++ b/nix/agent-modules/claude-settings.nix
@@ -209,7 +209,7 @@ in
 
   options.hyperhive.claudePlugins = lib.mkOption {
     type = lib.types.listOf lib.types.str;
-    default = [ ];
+    default = [ "skill-creator@claude-plugins-official" ];
     example = [
       "formatter@my-marketplace"
       "thinking-tools@anthropics"
@@ -223,6 +223,16 @@ in
       missing plugin is preferable to a non-serving agent. Rendered to
       `/etc/hyperhive/claude-plugins.json`; the harness reads it via
       `plugins::install_configured`.
+
+      Defaults to Anthropic's `skill-creator`, which teaches an agent
+      to write, refine, and evaluate its own skills — agents get it
+      out of the box, matching the default marketplace above.
+
+      Note that a per-agent definition REPLACES this default rather
+      than extending it (ordinary NixOS list-option semantics, same as
+      `claudeMarketplaces`). An agent that wants extra plugins AND the
+      default should list `skill-creator@claude-plugins-official`
+      alongside them.
     '';
   };