Fix dag validate singular task output

src/cortex-cli/src/agent_cmd/tests.rs

@@ -3,10 +3,9 @@
 #[cfg(test)]
 mod tests {
     use crate::agent_cmd::cli::{CopyArgs, ExportArgs};
-    use crate::agent_cmd::loader::{
-        load_builtin_agents, parse_frontmatter, read_file_with_encoding,
-    };
+    use crate::agent_cmd::loader::{load_builtin_agents, parse_frontmatter};
     use crate::agent_cmd::types::AgentMode;
+    use crate::utils::file::read_file_with_encoding;
 
     #[test]
     fn test_read_file_with_utf8() {

src/cortex-cli/src/dag_cmd/commands.rs

@@ -18,6 +18,14 @@ use super::helpers::{
 use super::scheduler::DagScheduler;
 use super::types::{DagOutputFormat, ExecutionStrategy};
 
+pub(super) fn task_count_label(count: usize) -> String {
+    if count == 1 {
+        "1 task".to_string()
+    } else {
+        format!("{} tasks", count)
+    }
+}
+
 /// Create a DAG from specification.
 pub async fn run_create(args: DagCreateArgs) -> Result<()> {
     let spec = load_spec(&args.file)?;
@@ -362,8 +370,8 @@ pub async fn run_validate(args: DagValidateArgs) -> Result<()> {
             match dag.topological_sort() {
                 Ok(order) => {
                     print_success(&format!(
-                        "✓ DAG is valid ({} tasks, no cycles detected)",
-                        dag.len()
+                        "✓ DAG is valid ({}, no cycles detected)",
+                        task_count_label(dag.len())
                     ));
 
                     if args.verbose {

src/cortex-cli/src/dag_cmd/tests.rs

@@ -5,6 +5,7 @@ use super::types::{DagSpecInput, TaskSpecInput};
 use cortex_agents::task::{DagHydrator, Task, TaskId, TaskSpec};
 use std::collections::HashMap;
 
+use super::commands::task_count_label;
 use super::executor::TaskExecutor;
 
 #[test]
@@ -78,6 +79,12 @@ fn test_dag_creation_with_cycle_detection() {
     assert!(result.is_err());
 }
 
+#[test]
+fn test_dag_validate_task_count_label_uses_singular_for_one_task() {
+    assert_eq!(task_count_label(1), "1 task");
+    assert_eq!(task_count_label(2), "2 tasks");
+}
+
 #[tokio::test]
 async fn test_task_executor() {
     let executor = TaskExecutor::new(30, false);