diff --git a/src-tauri/src/models/agent.rs b/src-tauri/src/models/agent.rs
index c199f8a..1e4c5e6 100644
--- a/src-tauri/src/models/agent.rs
+++ b/src-tauri/src/models/agent.rs
@@ -67,7 +67,13 @@ impl AgentTool {
 
     pub fn to_non_interactive_args(&self) -> Vec<String> {
         match self {
-            AgentTool::Codex => vec!["exec".to_string(), "-".to_string()],
+            AgentTool::Codex => vec![
+                "exec".to_string(),
+                "--ephemeral".to_string(),
+                "-c".to_string(),
+                "mcp_servers.tuleap.enabled=false".to_string(),
+                "-".to_string(),
+            ],
             AgentTool::ClaudeCode => vec!["-p".to_string()],
         }
     }
@@ -299,7 +305,13 @@ mod tests {
     fn test_non_interactive_args_match_cli_expectations() {
         assert_eq!(
             AgentTool::Codex.to_non_interactive_args(),
-            vec!["exec".to_string(), "-".to_string()]
+            vec![
+                "exec".to_string(),
+                "--ephemeral".to_string(),
+                "-c".to_string(),
+                "mcp_servers.tuleap.enabled=false".to_string(),
+                "-".to_string()
+            ]
         );
         assert_eq!(
             AgentTool::ClaudeCode.to_non_interactive_args(),
diff --git a/src-tauri/src/services/agent_runtime.rs b/src-tauri/src/services/agent_runtime.rs
index b4dc58c..63e6903 100644
--- a/src-tauri/src/services/agent_runtime.rs
+++ b/src-tauri/src/services/agent_runtime.rs
@@ -2,6 +2,19 @@ use tokio::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader};
 use tokio::process::Command;
 use tokio::time::{timeout, Duration};
 
+fn normalize_process_stderr(stderr: &str) -> String {
+    let trimmed = stderr.trim();
+    if trimmed.is_empty() {
+        return String::new();
+    }
+
+    if trimmed.contains("Cannot start a runtime from within a runtime") {
+        return "Le processus agent a plante avec un conflit de runtime Tokio. Orchai desactive MCP Tuleap sur les executions automatisees Codex ; relancez la tache. Si l'erreur persiste, mettez a jour ou desactivez le binaire local tuleap-mcp.".to_string();
+    }
+
+    trimmed.to_string()
+}
+
 pub async fn run_agent_command(
     command: &str,
     args: &[String],
@@ -31,7 +44,7 @@ pub async fn run_agent_command(
         .map_err(|e| format!("Failed to wait process output: {}", e))?;
 
     if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
+        let stderr = normalize_process_stderr(&String::from_utf8_lossy(&output.stderr));
         let code = output.status.code().unwrap_or(-1);
         if stderr.is_empty() {
             return Err(format!("CLI command exited with code {}", code));
@@ -118,7 +131,7 @@ where
         .map_err(|_| format!("CLI command timed out after {}s", timeout_secs))??;
 
     if !status.success() {
-        let stderr = stderr_output.trim().to_string();
+        let stderr = normalize_process_stderr(&stderr_output);
         let code = status.code().unwrap_or(-1);
         if stderr.is_empty() {
             return Err(format!("CLI command exited with code {}", code));
@@ -138,6 +151,19 @@ where
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_normalize_process_stderr_runtime_panic() {
+        let raw = "thread 'tokio-rt-worker' panicked\nCannot start a runtime from within a runtime";
+        let normalized = normalize_process_stderr(raw);
+        assert!(normalized.contains("conflit de runtime Tokio"));
+    }
+
+    #[test]
+    fn test_normalize_process_stderr_passthrough() {
+        let raw = "some other stderr";
+        assert_eq!(normalize_process_stderr(raw), "some other stderr");
+    }
+
     #[tokio::test]
     async fn test_run_agent_command_streaming_collects_chunks() {
         let args = vec!["-c".to_string(), "cat".to_string()];