Migrate plugin commands into skills on install (#33411)

## What changed

- Convert supported plugin command Markdown into generated skills when a plugin is installed.
- Read command sources from the manifest's `commands` field, falling back to the plugin's `commands/` directory.
- Load generated command skills alongside native plugin skills while preferring native skills with the same name.
- Skip commands with unsupported templates, missing descriptions, name collisions, or generated skills larger than 4 KB, and keep migration failures from blocking plugin installation.

## Testing

- Cover default and manifest-configured command paths, stale generated skill cleanup, size limits, native-skill precedence, invalid manifest fields, and non-fatal migration errors.

GitOrigin-RevId: 67d910048544b160b191066569bca69b2b951ebc

codex-rs/core-plugins/src/manager_tests.rs

@@ -1885,6 +1885,153 @@ async fn load_plugins_uses_manifest_configured_component_paths() {
     }
 }
 
+#[tokio::test]
+async fn install_plugin_materializes_default_command_skills() {
+    let codex_home = TempDir::new().unwrap();
+    let source_root = codex_home.path().join("source/sample");
+
+    write_file(
+        &source_root.join(".codex-plugin/plugin.json"),
+        r#"{
+  "name": "sample",
+  "skills": "./custom-skills/"
+}"#,
+    );
+    fs::create_dir_all(source_root.join("custom-skills")).unwrap();
+    write_file(
+        &source_root.join("custom-skills/source-command-pr-review/SKILL.md"),
+        "---\nname: source-command-pr-review\ndescription: Native review skill\n---\n",
+    );
+    write_file(
+        &source_root.join("commands/pr/review.md"),
+        "---\ndescription: Review a pull request\n---\nInspect the proposed changes.\n",
+    );
+    write_file(
+        &source_root.join("commands/summarize.md"),
+        "---\ndescription: Summarize a change\n---\nSummarize the proposed changes.\n",
+    );
+    write_file(
+        &source_root.join("commands/oversized.md"),
+        &format!("---\ndescription: Oversized\n---\n{}", "x".repeat(4_000)),
+    );
+    write_file(
+        &source_root.join(".codex-plugin/migrated-command-skills/undeclared-command/SKILL.md"),
+        "---\nname: undeclared-command\ndescription: undeclared command\n---\n",
+    );
+    let result = PluginStore::new(codex_home.path().to_path_buf())
+        .install(
+            source_root.abs(),
+            PluginId::parse("sample@test").expect("plugin id should parse"),
+        )
+        .unwrap();
+    let migrated_skill = result
+        .installed_path
+        .join(".codex-plugin/migrated-command-skills/source-command-pr-review/SKILL.md");
+    let expected_migrated_skill = "---\nname: \"source-command-pr-review\"\ndescription: \"Review a pull request\"\n---\n\n# source-command-pr-review\n\nUse this skill when the user asks to run the migrated source command `pr-review`.\n\n## Command Template\n\nInspect the proposed changes.\n";
+    assert_eq!(
+        fs::read_to_string(&migrated_skill).unwrap(),
+        expected_migrated_skill
+    );
+    assert!(
+        !result
+            .installed_path
+            .join(".codex-plugin/migrated-command-skills/undeclared-command")
+            .exists()
+    );
+    assert!(
+        !result
+            .installed_path
+            .join(".codex-plugin/migrated-command-skills/source-command-oversized")
+            .exists()
+    );
+
+    let manifest = crate::manifest::load_plugin_manifest(&result.installed_path).unwrap();
+    let resolved = load_plugin_skills(
+        &result.installed_path,
+        &result.plugin_id,
+        &manifest,
+        /*restriction_product*/ None,
+        &SkillConfigRules::default(),
+        /*plugin_skill_snapshots*/ None,
+        Arc::new(Semaphore::new(MAX_CONCURRENT_ROOT_SCANS)),
+    )
+    .await;
+    assert_eq!(
+        resolved
+            .skills
+            .iter()
+            .map(|skill| skill.path_to_skills_md.clone())
+            .collect::<Vec<_>>(),
+        vec![
+            AbsolutePathBuf::from_absolute_path_checked(
+                fs::canonicalize(
+                    result
+                        .installed_path
+                        .join("custom-skills/source-command-pr-review/SKILL.md")
+                )
+                .unwrap()
+            )
+            .unwrap(),
+            AbsolutePathBuf::from_absolute_path_checked(
+                fs::canonicalize(result.installed_path.join(
+                    ".codex-plugin/migrated-command-skills/source-command-summarize/SKILL.md"
+                ))
+                .unwrap()
+            )
+            .unwrap()
+        ]
+    );
+}
+
+#[test]
+fn install_plugin_ignores_invalid_commands_manifest_field() {
+    let codex_home = TempDir::new().unwrap();
+    let source_root = codex_home.path().join("source/sample");
+    write_file(
+        &source_root.join(".codex-plugin/plugin.json"),
+        r#"{"name":"sample","commands":{}}"#,
+    );
+    write_file(
+        &source_root.join("commands/review.md"),
+        "---\ndescription: Review\n---\nReview the current change.\n",
+    );
+
+    let result = PluginStore::new(codex_home.path().to_path_buf())
+        .install(
+            source_root.abs(),
+            PluginId::parse("sample@test").expect("plugin id should parse"),
+        )
+        .unwrap();
+
+    assert!(
+        !result
+            .installed_path
+            .join(".codex-plugin/migrated-command-skills")
+            .exists()
+    );
+}
+
+#[test]
+fn install_plugin_ignores_command_migration_errors() {
+    let codex_home = TempDir::new().unwrap();
+    let source_root = codex_home.path().join("source/sample");
+    write_file(
+        &source_root.join(".codex-plugin/plugin.json"),
+        r#"{"name":"sample","commands":"./commands/review.md"}"#,
+    );
+    fs::create_dir_all(source_root.join("commands")).unwrap();
+    fs::write(source_root.join("commands/review.md"), [0xff]).unwrap();
+
+    let result = PluginStore::new(codex_home.path().to_path_buf())
+        .install(
+            source_root.abs(),
+            PluginId::parse("sample@test").expect("plugin id should parse"),
+        )
+        .unwrap();
+
+    assert!(result.installed_path.join("commands/review.md").is_file());
+}
+
 #[tokio::test]
 async fn load_plugin_skills_dedupes_overlapping_manifest_roots() {
     let codex_home = TempDir::new().unwrap();
@@ -2851,6 +2998,10 @@ async fn install_plugin_writes_marketplace_manifest_fallback_when_missing_plugin
         "review skill",
     )
     .unwrap();
+    write_file(
+        &plugin_root.join("commands/review.md"),
+        "---\ndescription: Review code\n---\nReview the current change.\n",
+    );
     fs::write(
         repo_root.join(".agents/plugins/marketplace.json"),
         r#"{
@@ -2866,6 +3017,7 @@ async fn install_plugin_writes_marketplace_manifest_fallback_when_missing_plugin
       "skills": [
         "./skills/thermo-nuclear-code-quality-review"
       ],
+      "commands": ["./commands/review.md"],
       "category": "code-review"
     }
   ]
@@ -2931,6 +3083,14 @@ async fn install_plugin_writes_marketplace_manifest_fallback_when_missing_plugin
         serde_json::json!({ "name": "Byron Grogan" })
     );
     assert_eq!(fallback_json["category"], "code-review");
+    assert_eq!(
+        fs::read_to_string(
+            installed_path
+                .join(".codex-plugin/migrated-command-skills/source-command-review/SKILL.md")
+        )
+        .unwrap(),
+        "---\nname: \"source-command-review\"\ndescription: \"Review code\"\n---\n\n# source-command-review\n\nUse this skill when the user asks to run the migrated source command `review`.\n\n## Command Template\n\nReview the current change.\n"
+    );
 }
 
 #[tokio::test]