diff --git a/server/src/http/mcp.rs b/server/src/http/mcp.rs
index 8aa4aae..30ebd5a 100644
--- a/server/src/http/mcp.rs
+++ b/server/src/http/mcp.rs
@@ -2121,7 +2121,8 @@ fn add_permission_rule(project_root: &std::path::Path, rule: &str) -> Result<(),
 /// Rebuild the server binary and re-exec.
 ///
 /// 1. Gracefully stops all running agents (kills PTY children).
-/// 2. Runs `cargo build --release -p story-kit` from the workspace root.
+/// 2. Runs `cargo build [-p story-kit]` from the workspace root, matching
+///    the current build profile (debug or release).
 /// 3. If the build fails, returns the build error (server stays up).
 /// 4. If the build succeeds, re-execs the process with the new binary via
 ///    `std::os::unix::process::CommandExt::exec()`.
@@ -2152,12 +2153,19 @@ async fn tool_rebuild_and_restart(ctx: &AppContext) -> Result<String, String> {
         workspace_root.display()
     );
 
-    // 3. Run `cargo build --release -p story-kit`.
+    // 3. Build the server binary, matching the current build profile so the
+    //    re-exec via current_exe() picks up the new binary.
+    let build_args: Vec<&str> = if cfg!(debug_assertions) {
+        vec!["build", "-p", "story-kit"]
+    } else {
+        vec!["build", "--release", "-p", "story-kit"]
+    };
+    slog!("[rebuild] cargo {}", build_args.join(" "));
     let output = tokio::task::spawn_blocking({
         let workspace_root = workspace_root.to_path_buf();
         move || {
             std::process::Command::new("cargo")
-                .args(["build", "--release", "-p", "story-kit"])
+                .args(&build_args)
                 .current_dir(&workspace_root)
                 .output()
         }
@@ -4298,4 +4306,24 @@ stage = "coder"
         assert_eq!(ctx.agents.list_agents().unwrap().len(), 0);
         ctx.agents.kill_all_children(); // should not panic on empty pool
     }
+
+    #[test]
+    fn rebuild_uses_matching_build_profile() {
+        // The build must use the same profile (debug/release) as the running
+        // binary, otherwise cargo build outputs to a different target dir and
+        // current_exe() still points at the old binary.
+        let build_args: Vec<&str> = if cfg!(debug_assertions) {
+            vec!["build", "-p", "story-kit"]
+        } else {
+            vec!["build", "--release", "-p", "story-kit"]
+        };
+
+        // Tests always run in debug mode, so --release must NOT be present.
+        assert!(
+            !build_args.contains(&"--release"),
+            "In debug builds, rebuild must not pass --release (would put \
+             the binary in target/release/ while current_exe() points to \
+             target/debug/)"
+        );
+    }
 }