feat: migrate MCP implementation from mcp-types to rmcp

codex-rs/exec/src/event_processor_with_human_output.rs

@@ -375,7 +375,8 @@ impl EventProcessor for EventProcessorWithHumanOutput {
                 ts_msg!(self, "{}", title.style(title_style));
 
                 if let Ok(res) = result {
-                    let val: serde_json::Value = res.into();
+                    let val = serde_json::to_value(res)
+                        .unwrap_or_else(|_| serde_json::Value::String("<result>".to_string()));
                     let pretty =
                         serde_json::to_string_pretty(&val).unwrap_or_else(|_| val.to_string());
 

codex-rs/exec/src/exec_events.rs

@@ -1,5 +1,4 @@
 use codex_protocol::models::WebSearchAction;
-use mcp_types::ContentBlock as McpContentBlock;
 use serde::Deserialize;
 use serde::Serialize;
 use serde_json::Value as JsonValue;
@@ -256,7 +255,14 @@ pub struct CollabToolCallItem {
 /// Result payload produced by an MCP tool invocation.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, TS)]
 pub struct McpToolCallItemResult {
-    pub content: Vec<McpContentBlock>,
+    // NOTE: `rmcp::model::Content` (and its `RawContent` variants) would be a
+    // more precise Rust representation of MCP content blocks. We intentionally
+    // use `serde_json::Value` here because this crate exports JSON schema + TS
+    // types (`schemars`/`ts-rs`), and the rmcp model types aren't set up to be
+    // schema/TS friendly (and would introduce heavier coupling to rmcp's Rust
+    // representations). Using `JsonValue` keeps the payload wire-shaped and
+    // easy to export.
+    pub content: Vec<JsonValue>,
     pub structured_content: Option<JsonValue>,
 }