fix(skills): route [[skill]] + plugin skills natively for Codex/Gemini (ADR-012)

.claude/skills/nasde-benchmark-creator/SKILL.md

@@ -336,10 +336,14 @@ variants/gemini-baseline/
 
 > **Codex/Gemini skills are registered natively** (Harbor `config.agent.skills`),
 > not via `sandbox_files` — these CLIs auto-discover skills only from a
-> HOME-scoped dir, never from a `/app` cwd dir. Each `SKILL.md` **must start with
-> a `---` YAML frontmatter line**: Codex's loader rejects a file that opens with
-> anything else (`missing YAML frontmatter delimited by ---`) and silently skips
-> the skill. Put any provenance comment *below* the closing `---`. See
+> HOME-scoped dir, never from a `/app` cwd dir. This applies to **all** ways a
+> skill is supplied to a Codex/Gemini variant: the `agents_skills/` /
+> `gemini_skills/` snapshot above, a `[[skill]]` by-reference entry in
+> `variant.toml`, and a `[nasde.plugin]`'s own `skills/`. Each `SKILL.md`
+> **must start with a `---` YAML frontmatter line**: Codex's loader rejects a
+> file that opens with anything else (`missing YAML frontmatter delimited by
+> ---`) and silently skips the skill. Put any provenance comment *below* the
+> closing `---`. See
 > [ADR-012](../../../docs/adr/012-native-codex-gemini-skill-injection.md).
 
 If no `harbor_config.json` exists, `nasde` auto-generates one from `variant.toml`. To customize (e.g., add MCP servers), create it explicitly:

CHANGELOG.md

@@ -104,6 +104,23 @@ See [docs/RELEASING.md](docs/RELEASING.md) for the release procedure.
   max_turns` in `nasde.toml`. ([#54])
 
 ### Fixed
+- **`[[skill]]` by-reference and `[nasde.plugin]` skills now register natively for Codex/Gemini ([ADR-012](docs/adr/012-native-codex-gemini-skill-injection.md)).**
+  PR #65 fixed the *snapshot* path (`agents_skills/`, `gemini_skills/`) but left
+  the two other ways a skill reaches an agent — `[[skill]]` by-reference in
+  `variant.toml` and a `[nasde.plugin]`'s own `skills/` — still hardcoding
+  `/app/.claude/skills/` via `stage_skill_dir`. Correct for Claude (cwd discovery
+  root), but for a **Codex/Gemini** variant the skill landed where the CLI never
+  scans, so it was never natively registered (the same silent "skill-as-document"
+  failure). Both paths now resolve to skill *directories*
+  (`collect_referenced_skill_dirs` / `collect_plugin_skill_dirs`) routed through
+  Harbor's native `config.agent.skills` for Codex/Gemini, unioned with the
+  snapshot dirs under one `_nasde_derived_skills` marker (stale-drop +
+  hand-authored preservation work across both sources); Claude keeps its
+  unchanged `sandbox_files` path. The frontmatter warning now also fires on this
+  path, and a new warning flags two derived skill dirs sharing a basename (Harbor
+  registers only the last). New example variants `codex-nasde-dev-with-arch` and
+  `gemini-nasde-dev-with-arch` exercise `[[skill]]` by-reference on a non-Claude
+  agent. ([#67])
 - **Codex/Gemini skills are now natively registered ([ADR-012](docs/adr/012-native-codex-gemini-skill-injection.md)).**
   Codex and Gemini auto-discover skills only from a HOME-scoped directory
   (`$HOME/.agents/skills`, `~/.gemini/skills`), never from a `.agents/skills` /
@@ -522,4 +539,5 @@ Initial release under the **nasde-toolkit** name (rebrand from
 [#59]: https://github.com/NoesisVision/nasde-toolkit/pull/59
 [#61]: https://github.com/NoesisVision/nasde-toolkit/pull/61
 [#65]: https://github.com/NoesisVision/nasde-toolkit/pull/65
+[#67]: https://github.com/NoesisVision/nasde-toolkit/pull/67
 [gh-litellm-2026-04]: https://github.com/BerriAI/litellm/security/advisories/GHSA-xqmj-j6mv-4862

docs/adr/012-native-codex-gemini-skill-injection.md

@@ -94,6 +94,36 @@ skills and `[[skill]]` by-reference (ADR-009) via `stage_skill_dir`. Migrating
 it onto `config.agent.skills` would be a larger, riskier change with no
 behavioral payoff. Scope is kept to the actual bug.
 
+### All three skill paths, not just the snapshot
+
+A skill reaches an agent three ways: the variant **snapshot**
+(`agents_skills/`, `gemini_skills/`), **`[[skill]]` by-reference** in
+`variant.toml`, and a **`[nasde.plugin]`**'s own `skills/`. The first revision
+of this decision fixed only the snapshot path; the latter two still went
+through `stage_skill_dir`'s hardcoded `/app/.claude/skills/` and so were broken
+for Codex/Gemini in exactly the same way.
+
+All three are now routed natively for Codex/Gemini. `[[skill]]`/plugin skills
+are resolved to skill *directories* by `collect_referenced_skill_dirs` /
+`collect_plugin_skill_dirs` (the dir-list counterparts of the unchanged
+Claude-only `stage_referenced_skills` / `register_plugin_skills`), threaded as
+`extra_skill_dirs` and **unioned** with the snapshot dirs inside
+`_refresh_agent_skills`. The union is tracked by the single
+`_nasde_derived_skills` marker, so stale-drop and hand-authored preservation
+work across both sources. For a Claude agent `extra_skill_dirs` is dropped at
+merge time (those skills already ride `sandbox_files`, so feeding the native
+list too would double-inject). Because Harbor's `resolve_skills` keys skills by
+basename (last-wins), nasde warns when two derived dirs share a basename so the
+loser does not silently vanish.
+
+**Coverage note (honest).** The `[[skill]]` path is verified end-to-end on a
+live agent (see Consequences). The `[nasde.plugin]` path shares the same channel
+from `extra_skill_dirs` onward, but there is no example benchmark with a
+`[nasde.plugin]` to run it e2e — so it is covered by an **integration test** that
+drives the real `docker.ensure_task_plugin` staging → `collect_plugin_skill_dirs`
+→ harbor_config (no Docker build), plus unit tests on the resolver. Full
+live-agent e2e for a plugin is a follow-up for when a plugin benchmark exists.
+
 ### Frontmatter guardrail
 
 Codex's loader is strict: a `SKILL.md` that does not **start** with a `---`
@@ -123,18 +153,25 @@ comments moved below the closing `---`.
     its native mechanism, not by reading the file.
 - Skill×model matrix results for Codex/Gemini collected under the old behavior
   are invalid (skill-as-document, not skill-as-native) and must be re-run.
-- `sandbox_files` no longer carries skill files for Codex/Gemini; it carries
-  only `AGENTS.md` / `GEMINI.md` (and, for Claude, the unchanged skill files).
+- For Codex/Gemini, skills (snapshot, `[[skill]]`, and plugin) are all carried
+  by `config.agent.skills`; the agent's effective `sandbox_files` is just
+  `AGENTS.md` / `GEMINI.md`. The Claude `sandbox_files` skill map is still built
+  unconditionally (so Claude stays byte-identical and tested) but a Codex/Gemini
+  agent never consumes it.
 - The brittle `_expand_skill_targets` workaround in `ConfigurableGemini` (which
   hardcoded `/root/.gemini/skills/`) is removed — Harbor's native command uses
   the shell-expanded `$HOME`, correct for non-root users too.
 
 ## References
 
 - `runner._collect_native_skill_dirs`, `runner._refresh_agent_skills`,
-  `runner._agent_type_from_import_path`
+  `runner._agent_type_from_import_path`, `runner._referenced_skill_dirs_for_agent`,
+  `runner._warn_skill_basename_collisions`
+- `plugin_registration.collect_referenced_skill_dirs`,
+  `plugin_registration.collect_plugin_skill_dirs` (dir-list channel),
+  `stage_referenced_skills` / `register_plugin_skills` (unchanged Claude sink)
 - Harbor `agents/installed/codex.py::_build_register_skills_command`,
   `gemini_cli.py::_build_register_skills_command`, `trial.py` skill upload
 - `openai/codex` `core-skills/src/loader.rs` (native discovery roots)
-- [ADR-009](009-plugin-and-skill-by-reference.md) (the Claude skill path this
-  decision deliberately leaves untouched)
+- [ADR-009](009-plugin-and-skill-by-reference.md) (the `[[skill]]` / plugin
+  mechanism whose Claude sink this decision leaves untouched)

examples/nasde-dev-skill/variants/codex-nasde-dev-with-arch/AGENTS.md

@@ -0,0 +1,9 @@
+# Agent Instructions
+
+## Approach
+
+1. Begin by consulting the **nasde-dev** skill and apply its guidance throughout this task.
+2. Before writing any code, explore the existing codebase to understand its architecture and conventions.
+3. Follow existing architectural patterns exactly — match naming, namespaces, directory structure, and code style.
+4. When modifying nasde-toolkit functionality (CLI, runner, evaluator, config, agents), follow the `nasde-dev` skill's verification protocol, including documentation sync requirements.
+5. After making changes, verify documentation is consistent (CLAUDE.md, README.md, ARCHITECTURE.md).

examples/nasde-dev-skill/variants/codex-nasde-dev-with-arch/variant.toml

@@ -0,0 +1,9 @@
+agent = "codex"
+model = "gpt-5.4"
+
+# nasde-dev skill by-reference (ADR-009) from the live source. For a Codex
+# variant this is registered through Harbor's native config.agent.skills so
+# the skill lands in $HOME/.agents/skills and Codex auto-discovers it — NOT in
+# the /app cwd (which Codex never scans). See ADR-012.
+[[skill]]
+path = "../../../../.claude/skills/nasde-dev"

examples/nasde-dev-skill/variants/gemini-nasde-dev-with-arch/GEMINI.md

@@ -0,0 +1,9 @@
+# Agent Instructions
+
+## Approach
+
+1. Begin by consulting the **nasde-dev** skill and apply its guidance throughout this task.
+2. Before writing any code, explore the existing codebase to understand its architecture and conventions.
+3. Follow existing architectural patterns exactly — match naming, namespaces, directory structure, and code style.
+4. When modifying nasde-toolkit functionality (CLI, runner, evaluator, config, agents), follow the `nasde-dev` skill's verification protocol, including documentation sync requirements.
+5. After making changes, verify documentation is consistent (CLAUDE.md, README.md, ARCHITECTURE.md).

examples/nasde-dev-skill/variants/gemini-nasde-dev-with-arch/variant.toml

@@ -0,0 +1,9 @@
+agent = "gemini"
+model = "google/gemini-3-flash-preview"
+
+# nasde-dev skill by-reference (ADR-009) from the live source. For a Gemini
+# variant this is registered through Harbor's native config.agent.skills so
+# the skill lands in ~/.gemini/skills and Gemini auto-discovers it — NOT in
+# the /app cwd (which Gemini never scans). See ADR-012.
+[[skill]]
+path = "../../../../.claude/skills/nasde-dev"

src/nasde_toolkit/plugin_registration.py

@@ -11,11 +11,17 @@
 2. The ``[[skill]]`` array in variant.toml references a skill from a source
    path instead of copying it into ``variants/<v>/skills/``.
 
-Both feed :func:`stage_skill_dir`, which expands a skill directory into the
-flat ``{container_path: host_file}`` mapping ConfigurableClaude uploads
-(it only uploads regular files, mirroring ``_collect_codex_skills``). The
-plugin path additionally calls :func:`inject_mcp_server` to register the
-plugin's MCP server in the task's Harbor config.
+For **Claude** both feed :func:`stage_skill_dir`, which expands a skill
+directory into the flat ``{container_path: host_file}`` mapping
+ConfigurableClaude uploads to ``/app/.claude/skills`` (Claude's cwd discovery
+root). The plugin path additionally calls :func:`inject_mcp_server` to register
+the plugin's MCP server in the task's Harbor config.
+
+For **Codex/Gemini** the same skill *directories* are resolved by
+:func:`collect_referenced_skill_dirs` / :func:`collect_plugin_skill_dirs` and
+fed to Harbor's native ``config.agent.skills`` instead — those CLIs scan only a
+HOME-scoped dir (``$HOME/.agents/skills``, ``~/.gemini/skills``), never the
+``/app`` cwd the sandbox map targets. See ADR-012.
 """
 
 from __future__ import annotations
@@ -119,6 +125,54 @@ def stage_referenced_skills(
         console.print(f"  [dim]Registered referenced skill '{resolved.name}'[/dim]")
 
 
+def collect_referenced_skill_dirs(
+    variant_dir: Path,
+    worktree_factory: WorktreeFactory,
+) -> list[Path]:
+    """Resolve the ``[[skill]]`` array to a list of whole skill directories.
+
+    Same resolution as :func:`stage_referenced_skills` (each entry's ``path``
+    relative to the variant dir, optional ``ref`` read from a temporary git
+    worktree) but returns the resolved *directories* instead of flattening them
+    into a ``sandbox_files`` map under ``/app/.claude/skills``. Codex and Gemini
+    auto-discover skills only from a HOME-scoped dir, never from the agent's
+    ``/app`` cwd, so they take this dir list through Harbor's native
+    ``config.agent.skills`` mechanism. Claude keeps using
+    :func:`stage_referenced_skills`. See ADR-012.
+
+    Paths are fully ``resolve()``d so they compare equal to the snapshot dirs
+    from ``runner._collect_native_skill_dirs`` — the union/dedup, stale-drop and
+    basename-collision logic in ``_refresh_agent_skills`` key on string equality,
+    which would break on a symlinked ``/tmp`` (macOS) or a ``ref`` worktree path.
+    """
+    dirs: list[Path] = []
+    for entry in _read_skill_entries(variant_dir):
+        resolved = _resolve_skill_source(variant_dir, entry["path"], entry.get("ref", ""), worktree_factory)
+        if not (resolved / "SKILL.md").exists():
+            raise RuntimeError(f"[[skill]] '{resolved}' has no SKILL.md")
+        dirs.append(resolved.resolve())
+    return dirs
+
+
+def collect_plugin_skill_dirs(staged: StagedPlugin) -> list[Path]:
+    """Resolve a shipped plugin's own ``skills/`` to a list of skill dirs.
+
+    The dir-list counterpart of :func:`register_plugin_skills`, for the same
+    reason as :func:`collect_referenced_skill_dirs`: Codex/Gemini take these
+    dirs through Harbor's native ``config.agent.skills`` rather than a
+    cwd ``sandbox_files`` mapping. Paths are ``resolve()``d for the same
+    string-equality reason as :func:`collect_referenced_skill_dirs`.
+    """
+    skills_root = staged.staged_dir / "skills"
+    if not skills_root.is_dir():
+        return []
+    return [
+        skill_dir.resolve()
+        for skill_dir in sorted(skills_root.iterdir())
+        if skill_dir.is_dir() and (skill_dir / "SKILL.md").exists()
+    ]
+
+
 def inject_mcp_server(task_dir: Path, staged: StagedPlugin) -> None:
     """Write the plugin's MCP servers into the task's task.toml.