Parse model annotations from skill frontmatter (#38467)

## What changed

- Add an optional `model` field to parsed and loaded skill metadata.
- Recognize `model: luna` while ignoring unsupported model values without
  preventing the rest of the skill metadata from loading.

## Testing

- Cover supported, absent, unsupported, and repaired frontmatter model values.

GitOrigin-RevId: 376b65555e81d29a5eae93cc4c2633aacf7cd7c8

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

@@ -187,6 +187,7 @@ fn load_test_skill_root(root: &PluginSkillRoot) -> LoadedSkillRoot {
                         name: format!("{}:{}", root.plugin_namespace, parsed.name),
                         description: parsed.description,
                         short_description: parsed.short_description,
+                        model: parsed.model,
                         interface: None,
                         dependencies: None,
                         policy: None,

codex-rs/ext/skills/src/dynamic_skill_selector/character_routing_card_tests.rs

@@ -24,6 +24,7 @@ fn host_interface_metadata_makes_unlisted_workflow_discoverable() {
         name: "content-tools".to_string(),
         description: "Prepare visual content.".to_string(),
         short_description: None,
+        model: None,
         interface: Some(SkillInterface {
             display_name: Some("Visual Assets".to_string()),
             short_description: Some("Create illustrated assets.".to_string()),

codex-rs/ext/skills/src/host_roots_tests.rs

@@ -225,6 +225,7 @@ fn expected_skill(path: AbsolutePathBuf, name: &str, scope: SkillScope) -> Skill
         name: name.to_string(),
         description: format!("{name} description"),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,

codex-rs/ext/skills/src/host_service_tests.rs

@@ -324,6 +324,7 @@ async fn snapshot_for_config_preserves_host_precedence_for_symlinked_plugin_root
             name: "sample:search".to_string(),
             description: "shared skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,

codex-rs/ext/skills/src/loader/environment.rs

@@ -72,6 +72,7 @@ impl ParsedEnvironmentSkill {
             name: base_name,
             description,
             short_description,
+            model: _,
         } = parse_skill_frontmatter_metadata(&contents, || default_skill_name(&skill.path))
             .map_err(|err| err.to_string())?;
         let (dependencies, policy) = match &skill.metadata {
@@ -240,6 +241,7 @@ pub fn load_environment_skills_from_discovery(
             name: base_name,
             description,
             short_description,
+            model: _,
         } = match parse_skill_frontmatter_metadata(&skill.instructions.contents, || {
             default_skill_name(&skill.instructions.path)
         }) {

codex-rs/ext/skills/src/loader/host.rs

@@ -356,6 +356,7 @@ async fn parse_skill_file(
         name,
         description,
         short_description,
+        model,
     } = parse_skill_frontmatter_metadata(&contents, || default_skill_name(path))
         .map_err(|error| error.to_string())?;
     let LoadedSkillMetadata {
@@ -368,6 +369,7 @@ async fn parse_skill_file(
         name,
         description,
         short_description,
+        model,
         interface,
         dependencies,
         policy,

codex-rs/ext/skills/src/loader/host_io_tests.rs

@@ -84,6 +84,7 @@ async fn host_loading_reuses_walk_inventory_for_symlinked_skill_pack() {
                 name: "linked:first".to_string(),
                 description: "first skill.".to_string(),
                 short_description: None,
+                model: None,
                 interface: None,
                 dependencies: None,
                 policy: Some(SkillPolicy {
@@ -99,6 +100,7 @@ async fn host_loading_reuses_walk_inventory_for_symlinked_skill_pack() {
                 name: "linked:second".to_string(),
                 description: "second skill.".to_string(),
                 short_description: None,
+                model: None,
                 interface: None,
                 dependencies: None,
                 policy: None,

codex-rs/ext/skills/src/loader/host_tests.rs

@@ -7,6 +7,7 @@ use codex_protocol::protocol::SkillScope;
 use codex_skills::SkillDependencies;
 use codex_skills::SkillInterface;
 use codex_skills::SkillMetadata;
+use codex_skills::SkillModel;
 use codex_skills::SkillPolicy;
 use codex_skills::SkillToolDependency;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -107,7 +108,7 @@ async fn loads_host_frontmatter_dependencies_and_policy() {
     let skill_path = write_skill(
         &root,
         "demo",
-        "name: demo\ndescription: Demo skill\nmetadata:\n  short-description: Short demo",
+        "name: demo\ndescription: Demo skill\nmodel: luna\nmetadata:\n  short-description: Short demo",
     );
     write_metadata(
         &root,
@@ -134,6 +135,7 @@ policy:
             name: "demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: Some("Short demo".to_string()),
+            model: Some(SkillModel::Luna),
             interface: None,
             dependencies: Some(SkillDependencies {
                 tools: vec![SkillToolDependency {
@@ -173,6 +175,7 @@ async fn invalid_optional_metadata_fails_open() {
             name: "demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,
@@ -212,6 +215,7 @@ async fn loads_host_interface_metadata_and_local_asset_paths() {
             name: "demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
             interface: Some(SkillInterface {
                 display_name: Some("Demo".to_string()),
                 short_description: Some("Interface summary".to_string()),
@@ -251,6 +255,7 @@ async fn loads_plugin_skill_interface_icons_from_local_and_shared_assets() {
             name: "plugin:send-message".to_string(),
             description: "Send messages".to_string(),
             short_description: None,
+            model: None,
             interface: Some(SkillInterface {
                 display_name: None,
                 short_description: None,
@@ -293,6 +298,7 @@ async fn rejects_plugin_skill_interface_icons_outside_shared_assets() {
             name: "plugin:send-message".to_string(),
             description: "Send messages".to_string(),
             short_description: None,
+            model: None,
             interface: Some(SkillInterface {
                 display_name: Some("Send Message".to_string()),
                 short_description: None,
@@ -330,6 +336,7 @@ async fn rejects_interface_fields_that_escape_or_fail_validation() {
             name: "demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,
@@ -380,6 +387,7 @@ async fn discovers_nested_plugin_namespace_without_plugin_identity() {
             name: "plugin-name:demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,
@@ -425,6 +433,7 @@ async fn plugin_root_accepts_maximum_length_qualified_skill_name() {
             name: format!("{plugin_namespace}:{skill_name}"),
             description: "Search skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,
@@ -519,6 +528,7 @@ async fn recursive_plugin_root_preserves_owner_namespace_and_shared_asset_policy
             name: "plugin:demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
             interface: Some(SkillInterface {
                 display_name: None,
                 short_description: None,
@@ -578,6 +588,7 @@ async fn direct_child_plugin_root_ignores_nested_skills() {
             name: "plugin:direct".to_string(),
             description: "Direct skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,
@@ -659,6 +670,7 @@ async fn recursive_plugin_root_preserves_symlinked_skill_discovery_path() {
             name: "plugin:demo".to_string(),
             description: "Symlinked skill".to_string(),
             short_description: None,
+            model: None,
             interface: None,
             dependencies: None,
             policy: None,

codex-rs/ext/skills/tests/skills_extension.rs

@@ -171,6 +171,7 @@ async fn installed_extension_uses_host_service_snapshot() -> TestResult {
         name: "demo".to_string(),
         description: "Demo skill.".to_string(),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,
@@ -252,6 +253,7 @@ async fn host_world_state_records_catalog_metrics_on_publish_and_change() -> Tes
         name: "demo".to_string(),
         description: "Demo skill.".to_string(),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,
@@ -316,6 +318,7 @@ async fn host_world_state_records_catalog_metrics_on_publish_and_change() -> Tes
         name: "other".to_string(),
         description: "Other skill.".to_string(),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,
@@ -368,6 +371,7 @@ async fn persisted_host_snapshot_deduplicates_warning_after_reinitialization() -
         name: "demo".to_string(),
         description: "Demo skill.".to_string(),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,

codex-rs/skills/src/invocation_tests.rs

@@ -28,6 +28,7 @@ fn test_skill_metadata(skill_doc_path: AbsolutePathBuf) -> SkillMetadata {
         name: "test-skill".to_string(),
         description: "test".to_string(),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,

codex-rs/skills/src/lib.rs

@@ -3,6 +3,7 @@ mod invocation;
 mod loading;
 mod mentions;
 mod model;
+mod model_delegation;
 mod name_counts;
 mod parser;
 mod selection;
@@ -36,6 +37,7 @@ pub use model::SkillInterface;
 pub use model::SkillMetadata;
 pub use model::SkillPolicy;
 pub use model::SkillToolDependency;
+pub use model_delegation::SkillModel;
 pub use name_counts::build_skill_name_counts;
 pub use parser::ParsedSkillFrontmatter;
 pub use parser::SkillParseError;

codex-rs/skills/src/model.rs

@@ -1,3 +1,4 @@
+use crate::SkillModel;
 use codex_protocol::protocol::Product;
 use codex_protocol::protocol::SkillScope;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -9,6 +10,8 @@ pub struct SkillMetadata {
     pub name: String,
     pub description: String,
     pub short_description: Option<String>,
+    /// Optional model requested by this skill's frontmatter.
+    pub model: Option<SkillModel>,
     pub interface: Option<SkillInterface>,
     pub dependencies: Option<SkillDependencies>,
     pub policy: Option<SkillPolicy>,

codex-rs/skills/src/model_delegation.rs

@@ -0,0 +1,12 @@
+use serde::Deserialize;
+
+/// Model requested for work governed by a skill.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum SkillModel {
+    Luna,
+}
+
+#[cfg(test)]
+#[path = "model_delegation_tests.rs"]
+mod tests;

codex-rs/skills/src/model_delegation_tests.rs

@@ -0,0 +1,59 @@
+use pretty_assertions::assert_eq;
+
+use super::SkillModel;
+use crate::ParsedSkillFrontmatter;
+use crate::parse_skill_frontmatter_metadata;
+
+#[test]
+fn parses_supported_luna_skill_model() {
+    let contents = "---\nname: demo\ndescription: Demo skill\nmodel: luna\n---\n";
+
+    assert_eq!(
+        parse_skill_frontmatter_metadata(contents, || "fallback".to_string())
+            .unwrap()
+            .model,
+        Some(SkillModel::Luna)
+    );
+}
+
+#[test]
+fn permits_skills_without_a_model_annotation() {
+    let contents = "---\nname: demo\ndescription: Demo skill\n---\n";
+
+    assert_eq!(
+        parse_skill_frontmatter_metadata(contents, || "fallback".to_string())
+            .unwrap()
+            .model,
+        None
+    );
+}
+
+#[test]
+fn rejects_unsupported_model_without_disabling_ordinary_skill_loading() {
+    for unsupported_model in ["terra", "sol", "unknown"] {
+        let contents =
+            format!("---\nname: demo\ndescription: Demo skill\nmodel: {unsupported_model}\n---\n");
+
+        assert_eq!(
+            parse_skill_frontmatter_metadata(&contents, || "fallback".to_string()).unwrap(),
+            ParsedSkillFrontmatter {
+                name: "demo".to_string(),
+                description: "Demo skill".to_string(),
+                short_description: None,
+                model: None,
+            }
+        );
+    }
+}
+
+#[test]
+fn reuses_existing_frontmatter_scalar_repair() {
+    let contents = "---\nname: demo\ndescription: Build for AWS: ECS\nmodel: luna\n---\n";
+
+    assert_eq!(
+        parse_skill_frontmatter_metadata(contents, || "fallback".to_string())
+            .unwrap()
+            .model,
+        Some(SkillModel::Luna)
+    );
+}

codex-rs/skills/src/parser.rs

@@ -1,3 +1,4 @@
+use crate::SkillModel;
 use serde::Deserialize;
 use thiserror::Error;
 
@@ -10,6 +11,8 @@ struct SkillFrontmatter {
     #[serde(default)]
     description: Option<String>,
     #[serde(default)]
+    model: Option<serde_yaml::Value>,
+    #[serde(default)]
     metadata: SkillFrontmatterMetadata,
 }
 
@@ -25,6 +28,7 @@ pub struct ParsedSkillFrontmatter {
     pub name: String,
     pub description: String,
     pub short_description: Option<String>,
+    pub model: Option<SkillModel>,
 }
 
 /// Error produced while parsing or validating `SKILL.md` metadata.
@@ -88,6 +92,13 @@ pub fn parse_skill_frontmatter_metadata(
         name,
         description,
         short_description,
+        model: parsed.model.and_then(|model| {
+            serde_yaml::from_value(model)
+                .inspect_err(|error| {
+                    tracing::warn!(%error, "ignoring invalid skill model annotation");
+                })
+                .ok()
+        }),
     })
 }
 

codex-rs/skills/src/parser_tests.rs

@@ -17,6 +17,7 @@ fn parses_repairs_and_sanitizes_frontmatter() {
             name: "deploy service".to_string(),
             description: "Build for AWS: ECS".to_string(),
             short_description: Some("Deploy safely".to_string()),
+            model: None,
         }
     );
 }
@@ -33,6 +34,7 @@ fn uses_default_name_and_requires_description() {
             name: "demo".to_string(),
             description: "Demo skill".to_string(),
             short_description: None,
+            model: None,
         }
     );
 
@@ -56,6 +58,7 @@ fn repairs_short_descriptions_containing_colons_and_apostrophes() {
             name: "short".to_string(),
             description: "Short skill".to_string(),
             short_description: Some("What's included: builds and tests".to_string()),
+            model: None,
         }
     );
 }
@@ -74,6 +77,7 @@ fn repairs_unrecognized_frontmatter_fields_that_need_quotes() {
             name: "unknown".to_string(),
             description: "Unknown fields".to_string(),
             short_description: None,
+            model: None,
         }
     );
 }
@@ -92,6 +96,7 @@ fn preserves_block_scalar_bodies_while_repairing_other_fields() {
             name: "block".to_string(),
             description: "Build for AWS: ECS".to_string(),
             short_description: None,
+            model: None,
         }
     );
 }
@@ -114,6 +119,7 @@ fn preserves_overlong_descriptions_and_short_descriptions() {
             name: "long".to_string(),
             description,
             short_description: Some(short_description),
+            model: None,
         }
     );
 }

codex-rs/skills/src/selection_tests.rs

@@ -32,6 +32,7 @@ fn make_skill(name: &str, path: &str) -> SkillMetadata {
         name: name.to_string(),
         description: format!("{name} skill"),
         short_description: None,
+        model: None,
         interface: None,
         dependencies: None,
         policy: None,