agent: pull in and allow claude-code only for the claude runtime

docs/getting-started/nixos.md

@@ -39,8 +39,9 @@ nixosConfigurations.my-host = nixpkgs.lib.nixosSystem {
 };
 ```
 
-`claude-code` is unfree. Hyperhive scopes the allowance to itself, so you
-don't set `allowUnfree`.
+`claude-code` is unfree. Hyperhive scopes the allowance to itself, and only
+for agents that run claude (`services.hyperhive.agent.runtime = "claude"`, the
+default), so you don't set `allowUnfree`.
 
 ## 3 · Set the required options
 

nix/agent-modules/default.nix

@@ -41,6 +41,10 @@ let
     queue option. Remove the setting.
   '';
 
+  # Only a claude-runtime agent runs the binary. ACP subagents run on the
+  # parent agent's runtime, so they need no claude either.
+  runsClaude = config.services.hyperhive.agent.runtime == "claude";
+
   # `claude` on PATH. A hive that pins a claude-code
   # (`services.hyperhive.deploy.hive-controller.claudeCodePackage`) hands its
   # store path over at container start as `HYPERHIVE_CLAUDE_CODE_PATH`, and
@@ -237,7 +241,10 @@ in
     # evaluates its own `nixpkgs` instance, so the operator's host-level
     # `nixpkgs.config.allowUnfreePredicate` does not propagate into here —
     # we have to allow it inside the container's config as well.
-    nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (pkgs.lib.getName pkg) [ "claude-code" ];
+    # Only an agent that runs claude needs it: `runtime = "acp"` never
+    # references the package, so it is neither built nor allowed there.
+    nixpkgs.config.allowUnfreePredicate =
+      pkg: runsClaude && builtins.elem (pkgs.lib.getName pkg) [ "claude-code" ];
 
     # Core tooling every agent gets. Per-bin split packages (see
     # nix/packages/default.nix + ./packages.nix) rather than the full
@@ -256,9 +263,7 @@ in
     environment.systemPackages = [
       config.services.hyperhive.agent.packages.hive-metric
     ]
-    ++ [
-      claude
-    ]
+    ++ lib.optional runsClaude claude
     ++ (with pkgs; [
       bashInteractive
       coreutils-full

nix/module-eval/agent-runtime.nix

@@ -83,6 +83,9 @@ let
     };
   };
 
+  hasClaude = machine: lib.any (p: (p.name or "") == "claude") machine.environment.systemPackages;
+  allowsClaudeCode = machine: machine.nixpkgs.config.allowUnfreePredicate { pname = "claude-code"; };
+
   subagent = machine: machine.systemd.services.hive-subagent-daemon;
   harness = machine: machine.systemd.services.hive-agent;
   runtimeVars = [
@@ -234,6 +237,21 @@ let
         && !(lib.hasInfix "rm -f \"$earlier\"" s)
         && !(lib.hasInfix "mv -f \"$staged\" \"$earlier\"" s);
     }
+    {
+      name = "an ACP agent has no claude on PATH and no unfree allowance for claude-code";
+      ok = !(hasClaude acp) && !(allowsClaudeCode acp) && !(allowsClaudeCode opencode);
+    }
+    {
+      # Presence control for the case above: the same lookups find both on a
+      # claude agent, and the allowance is for claude-code alone.
+      name = "a claude agent has claude on PATH and an unfree allowance for claude-code only";
+      ok =
+        hasClaude claude
+        && hasClaude claudeApiKey
+        && allowsClaudeCode claude
+        && allowsClaudeCode claudeApiKey
+        && !(claude.nixpkgs.config.allowUnfreePredicate { pname = "other-unfree"; });
+    }
   ];
 in
 runGroup "agent-runtime" cases