Mcp protocol (#1715)

- Add typed MCP protocol surface in
`codex-rs/mcp-server/src/mcp_protocol.rs` for `requests`, `responses`,
and `notifications`
- Requests: `NewConversation`, `Connect`, `SendUserMessage`,
`GetConversations`
- Message content parts: `Text`, `Image` (`ImageUrl`/`FileId`, optional
`ImageDetail`), File (`Url`/`Id`/`inline Data`)
- Responses: `ToolCallResponseEnvelope` with optional `isError` and
`structuredContent` variants (`NewConversation`, `Connect`,
`SendUserMessageAccepted`, `GetConversations`)
- Notifications: `InitialState`, `ConnectionRevoked`, `CodexEvent`,
`Cancelled`
- Uniform `_meta` on `notifications` via `NotificationMeta`
(`conversationId`, `requestId`)
- Unit tests validate JSON wire shapes for key
`requests`/`responses`/`notifications`

codex-rs/Cargo.lock

@@ -822,6 +822,7 @@ dependencies = [
  "serde",
  "serde_json",
  "shlex",
+ "strum_macros 0.27.2",
  "tempfile",
  "tokio",
  "tokio-test",

codex-rs/core/src/config_types.rs

@@ -78,7 +78,7 @@ pub enum HistoryPersistence {
 #[derive(Deserialize, Debug, Clone, PartialEq, Default)]
 pub struct Tui {}
 
-#[derive(Deserialize, Debug, Clone, Copy, PartialEq, Default)]
+#[derive(Deserialize, Debug, Clone, Copy, PartialEq, Default, Serialize)]
 #[serde(rename_all = "kebab-case")]
 pub enum SandboxMode {
     #[serde(rename = "read-only")]

codex-rs/mcp-server/Cargo.toml

@@ -34,6 +34,7 @@ tokio = { version = "1", features = [
     "signal",
 ] }
 uuid = { version = "1", features = ["serde", "v4"] }
+strum_macros = "0.27.2"
 
 [dev-dependencies]
 assert_cmd = "2"

codex-rs/mcp-server/src/lib.rs

@@ -19,6 +19,7 @@ mod codex_tool_config;
 mod codex_tool_runner;
 mod exec_approval;
 mod json_to_toml;
+mod mcp_protocol;
 mod message_processor;
 mod outgoing_message;
 mod patch_approval;