fix(onboarding): require a skill_id for terminal session statuses

clap derives Vec<String> as optional, so `sessions create` would post an
empty skill_ids and defer the error to the backend. Mirror the API's
SessionStatus.IsTerminal() rule client-side: require at least one
--skill-id for completed/failed/abandoned, still allow empty for
in_progress.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: tedkahwaji

src/commands/onboarding.rs

@@ -9,6 +9,8 @@ const SKILLS_PATH: &str = "/api/v2/onboarding/skills";
 const SESSIONS_PATH: &str = "/api/v2/onboarding/sessions";
 
 const VALID_STATUSES: &[&str] = &["in_progress", "completed", "failed", "abandoned"];
+// Terminal statuses require at least one skill_id; the backend allows in_progress to be empty.
+const TERMINAL_STATUSES: &[&str] = &["completed", "failed", "abandoned"];
 const VALID_INTENTS: &[&str] = &["explore", "install", "reference"];
 
 /// List the available Datadog onboarding skills (`GET /api/v2/onboarding/skills`).
@@ -73,6 +75,10 @@ pub async fn sessions_create(
         );
     }
 
+    if TERMINAL_STATUSES.contains(&status) && skill_ids.is_empty() {
+        anyhow::bail!("at least one --skill-id is required when status is '{status}'");
+    }
+
     let mut attributes = serde_json::json!({
         "skill_ids": skill_ids,
         "summary": summary,
@@ -301,4 +307,47 @@ mod tests {
         assert!(err.contains("invalid status"), "got: {err}");
         cleanup_env();
     }
+
+    #[tokio::test]
+    async fn sessions_create_terminal_requires_skill_id() {
+        let _lock = lock_env().await;
+        let server = mockito::Server::new_async().await;
+        let cfg = test_config(&server.url());
+        let result =
+            super::sessions_create(&cfg, "run-123", &[], "summary", "completed", None).await;
+        let err = result.unwrap_err().to_string();
+        assert!(err.contains("at least one --skill-id"), "got: {err}");
+        cleanup_env();
+    }
+
+    #[tokio::test]
+    async fn sessions_create_in_progress_allows_empty_skill_ids() {
+        let _lock = lock_env().await;
+        let mut server = mockito::Server::new_async().await;
+        let cfg = test_config(&server.url());
+        let mock = server
+            .mock("POST", "/api/v2/onboarding/sessions")
+            .match_body(mockito::Matcher::PartialJson(serde_json::json!({
+                "data": {
+                    "type": "onboarding_session",
+                    "id": "run-123",
+                    "attributes": { "status": "in_progress", "skill_ids": [] },
+                },
+            })))
+            .with_status(201)
+            .with_header("content-type", "application/vnd.api+json")
+            .with_body(r#"{"data":{"id":"run-123"}}"#)
+            .create_async()
+            .await;
+        let result =
+            super::sessions_create(&cfg, "run-123", &[], "session started", "in_progress", None)
+                .await;
+        assert!(
+            result.is_ok(),
+            "in_progress create failed: {:?}",
+            result.err()
+        );
+        mock.assert_async().await;
+        cleanup_env();
+    }
 }

src/main.rs

@@ -6537,7 +6537,7 @@ enum OnboardingSessionsActions {
         /// Session (onboarding run) ID
         #[arg(long)]
         session_id: String,
-        /// Skill ID touched in this session (repeat for multiple)
+        /// Skill ID touched in this session (repeat for multiple; required unless status is in_progress)
         #[arg(long = "skill-id")]
         skill_ids: Vec<String>,
         /// Short summary of the session outcome