Support external agent config detect and import (#12660)

Migration Behavior

* Config
  *  Migrates settings.json into config.toml
* Only adds fields when config.toml is missing, or when those fields are
missing from the existing file
  *  Supported mappings:
    env -> shell_environment_policy
     sandbox.enabled = true -> sandbox_mode = "workspace-write"

* Skills
  *  Copies home and repo .claude/skills into .agents/skills
  *  Existing skill directories are not overwritten
  *  SKILL.md content is rewritten from Claude-related terms to Codex

* AgentsMd
  *  Repo only
  *  Migrates CLAUDE.md into AGENTS.md
* Detect/import only proceed when AGENTS.md is missing or present but
empty
  *  Content is rewritten from Claude-related terms to Codex

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -350,6 +350,14 @@ client_request_definitions! {
         params: v2::ConfigReadParams,
         response: v2::ConfigReadResponse,
     },
+    ExternalAgentConfigDetect => "externalAgentConfig/detect" {
+        params: v2::ExternalAgentConfigDetectParams,
+        response: v2::ExternalAgentConfigDetectResponse,
+    },
+    ExternalAgentConfigImport => "externalAgentConfig/import" {
+        params: v2::ExternalAgentConfigImportParams,
+        response: v2::ExternalAgentConfigImportResponse,
+    },
     ConfigValueWrite => "config/value/write" {
         params: v2::ConfigValueWriteParams,
         response: v2::ConfigWriteResponse,

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -640,6 +640,64 @@ pub struct ConfigRequirementsReadResponse {
     pub requirements: Option<ConfigRequirements>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, Hash, JsonSchema, TS)]
+#[ts(export_to = "v2/")]
+pub enum ExternalAgentConfigMigrationItemType {
+    #[serde(rename = "AGENTS_MD")]
+    #[ts(rename = "AGENTS_MD")]
+    AgentsMd,
+    #[serde(rename = "CONFIG")]
+    #[ts(rename = "CONFIG")]
+    Config,
+    #[serde(rename = "SKILLS")]
+    #[ts(rename = "SKILLS")]
+    Skills,
+    #[serde(rename = "MCP_SERVER_CONFIG")]
+    #[ts(rename = "MCP_SERVER_CONFIG")]
+    McpServerConfig,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExternalAgentConfigMigrationItem {
+    pub item_type: ExternalAgentConfigMigrationItemType,
+    pub description: String,
+    /// Null or empty means home-scoped migration; non-empty means repo-scoped migration.
+    pub cwd: Option<PathBuf>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExternalAgentConfigDetectResponse {
+    pub items: Vec<ExternalAgentConfigMigrationItem>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExternalAgentConfigDetectParams {
+    /// If true, include detection under the user's home (~/.claude, ~/.codex, etc.).
+    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+    pub include_home: bool,
+    /// Zero or more working directories to include for repo-scoped detection.
+    #[ts(optional = nullable)]
+    pub cwds: Option<Vec<PathBuf>>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExternalAgentConfigImportParams {
+    pub migration_items: Vec<ExternalAgentConfigMigrationItem>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct ExternalAgentConfigImportResponse {}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]