From b8cb89f2c4f7006b17b4aa5d8b39b95b93b559d8 Mon Sep 17 00:00:00 2001
From: Austin Horstman <khaneliman12@gmail.com>
Date: Tue, 24 Mar 2026 10:19:38 -0500
Subject: [PATCH] codex: support store-path skill sources

Handle per-skill values that come through as store-path strings, such as fetcher outputs with subdirectories appended. This restores the previously working pattern for packaged skill directories and adds a regression test for both directory and file sources.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>
---
 modules/programs/codex.nix                    |  8 +++--
 tests/modules/programs/codex/default.nix      |  1 +
 .../programs/codex/skills-store-path.nix      | 34 +++++++++++++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 tests/modules/programs/codex/skills-store-path.nix

diff --git a/modules/programs/codex.nix b/modules/programs/codex.nix
index c238c144..7dfe9dba 100644
--- a/modules/programs/codex.nix
+++ b/modules/programs/codex.nix
@@ -150,9 +150,13 @@ in
       # TODO: Remove this workaround once Codex supports symlinked SKILL.md
       # files again. Upstream only supports symlinking the containing skill
       # directory today: https://github.com/openai/codex/issues/10470
+      isStorePathString = content: builtins.isString content && lib.hasPrefix builtins.storeDir content;
+      isPathLikeContent = content: lib.isPath content || isStorePathString content;
       mkSkillDir =
         content:
-        pkgs.writeTextDir "SKILL.md" (if lib.isPath content then builtins.readFile content else content);
+        pkgs.writeTextDir "SKILL.md" (
+          if isPathLikeContent content then builtins.readFile content else content
+        );
       skillSources =
         if builtins.isAttrs cfg.skills then
           cfg.skills
@@ -162,7 +166,7 @@ in
           { };
       mkSkillEntry =
         name: content:
-        if lib.isPath content && lib.pathIsDirectory content then
+        if isPathLikeContent content && lib.pathIsDirectory content then
           lib.nameValuePair "${skillsDir}/${name}" {
             source = content;
           }
diff --git a/tests/modules/programs/codex/default.nix b/tests/modules/programs/codex/default.nix
index 86e6e623..756b3426 100644
--- a/tests/modules/programs/codex/default.nix
+++ b/tests/modules/programs/codex/default.nix
@@ -9,5 +9,6 @@
   codex-skills-inline-null-package = ./skills-inline-null-package.nix;
   codex-skills-inline-legacy-path = ./skills-inline-legacy-path.nix;
   codex-skills-dir = ./skills-dir.nix;
+  codex-skills-store-path = ./skills-store-path.nix;
   codex-skills-path-not-directory = ./skills-path-not-directory.nix;
 }
diff --git a/tests/modules/programs/codex/skills-store-path.nix b/tests/modules/programs/codex/skills-store-path.nix
new file mode 100644
index 00000000..3eb654ac
--- /dev/null
+++ b/tests/modules/programs/codex/skills-store-path.nix
@@ -0,0 +1,34 @@
+{ pkgs, ... }:
+let
+  src = pkgs.writeTextDir "skills/external-skill/SKILL.md" ''
+    ---
+    name: external-skill
+    description: Store path skill fixture.
+    ---
+
+    # External Skill
+
+    This content simulates a skill living inside a package source.
+  '';
+in
+{
+  programs.codex = {
+    enable = true;
+    skills = {
+      dir-skill = "${src}/skills/external-skill";
+      file-skill = "${src}/skills/external-skill/SKILL.md";
+    };
+  };
+
+  nmt.script = ''
+    assertLinkExists home-files/.agents/skills/dir-skill
+    assertFileExists home-files/.agents/skills/dir-skill/SKILL.md
+    assertFileContent home-files/.agents/skills/dir-skill/SKILL.md \
+      "${src}/skills/external-skill/SKILL.md"
+
+    assertLinkExists home-files/.agents/skills/file-skill
+    assertFileExists home-files/.agents/skills/file-skill/SKILL.md
+    assertFileContent home-files/.agents/skills/file-skill/SKILL.md \
+      "${src}/skills/external-skill/SKILL.md"
+  '';
+}