diff --git a/codex-rs/mcp-server/src/exec_approval.rs b/codex-rs/mcp-server/src/exec_approval.rs
index f073214b..54abfb35 100644
--- a/codex-rs/mcp-server/src/exec_approval.rs
+++ b/codex-rs/mcp-server/src/exec_approval.rs
@@ -18,7 +18,7 @@ use crate::codex_tool_runner::INVALID_PARAMS_ERROR_CODE;
 
 /// Conforms to [`mcp_types::ElicitRequestParams`] so that it can be used as the
 /// `params` field of an [`ElicitRequest`].
-#[derive(Debug, Serialize)]
+#[derive(Debug, Deserialize, Serialize)]
 pub struct ExecApprovalElicitRequestParams {
     // These fields are required so that `params`
     // conforms to ElicitRequestParams.
diff --git a/codex-rs/mcp-server/tests/codex_tool.rs b/codex-rs/mcp-server/tests/codex_tool.rs
index 7d59ff20..fc992a8c 100644
--- a/codex-rs/mcp-server/tests/codex_tool.rs
+++ b/codex-rs/mcp-server/tests/codex_tool.rs
@@ -89,14 +89,18 @@ async fn shell_command_approval_triggers_elicitation() -> anyhow::Result<()> {
     // This is the first request from the server, so the id should be 0 given
     // how things are currently implemented.
     let elicitation_request_id = RequestId::Integer(0);
+    let params = serde_json::from_value::<ExecApprovalElicitRequestParams>(
+        elicitation_request
+            .params
+            .clone()
+            .ok_or_else(|| anyhow::anyhow!("elicitation_request.params must be set"))?,
+    )?;
     let expected_elicitation_request = create_expected_elicitation_request(
         elicitation_request_id.clone(),
         shell_command.clone(),
         workdir_for_shell_function_call.path(),
         codex_request_id.to_string(),
-        // Internal Codex id: empirically it is 1, but this is
-        // admittedly an internal detail that could change.
-        "1".to_string(),
+        params.codex_event_id.clone(),
     )?;
     assert_eq!(expected_elicitation_request, elicitation_request);