[mcp-server] Update read config interface (#3093)

## Summary
Follow-up to #3056

This PR updates the mcp-server interface for reading the config settings
saved by the user. At risk of introducing _another_ Config struct, I
think it makes sense to avoid tying our protocol to ConfigToml, as its
become a bit unwieldy. GetConfigTomlResponse was a de-facto struct for
this already - better to make it explicit, in my opinion.

This is technically a breaking change of the mcp-server protocol, but
given the previous interface was introduced so recently in #2725, and we
have not yet even started to call it, I propose proceeding with the
breaking change - but am open to preserving the old endpoint.

## Testing
- [x] Added additional integration test coverage

codex-rs/core/src/config.rs

@@ -20,6 +20,8 @@ use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode;
 use codex_protocol::config_types::Verbosity;
 use codex_protocol::mcp_protocol::AuthMode;
+use codex_protocol::mcp_protocol::Tools;
+use codex_protocol::mcp_protocol::UserSavedConfig;
 use dirs::home_dir;
 use serde::Deserialize;
 use std::collections::HashMap;
@@ -503,6 +505,29 @@ pub struct ConfigToml {
     pub disable_paste_burst: Option<bool>,
 }
 
+impl From<ConfigToml> for UserSavedConfig {
+    fn from(config_toml: ConfigToml) -> Self {
+        let profiles = config_toml
+            .profiles
+            .into_iter()
+            .map(|(k, v)| (k, v.into()))
+            .collect();
+
+        Self {
+            approval_policy: config_toml.approval_policy,
+            sandbox_mode: config_toml.sandbox_mode,
+            sandbox_settings: config_toml.sandbox_workspace_write.map(From::from),
+            model: config_toml.model,
+            model_reasoning_effort: config_toml.model_reasoning_effort,
+            model_reasoning_summary: config_toml.model_reasoning_summary,
+            model_verbosity: config_toml.model_verbosity,
+            tools: config_toml.tools.map(From::from),
+            profile: config_toml.profile,
+            profiles,
+        }
+    }
+}
+
 #[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
 pub struct ProjectConfig {
     pub trust_level: Option<String>,
@@ -518,6 +543,15 @@ pub struct ToolsToml {
     pub view_image: Option<bool>,
 }
 
+impl From<ToolsToml> for Tools {
+    fn from(tools_toml: ToolsToml) -> Self {
+        Self {
+            web_search: tools_toml.web_search,
+            view_image: tools_toml.view_image,
+        }
+    }
+}
+
 impl ConfigToml {
     /// Derive the effective sandbox policy from the configuration.
     fn derive_sandbox_policy(&self, sandbox_mode_override: Option<SandboxMode>) -> SandboxPolicy {

codex-rs/core/src/config_profile.rs

@@ -22,3 +22,18 @@ pub struct ConfigProfile {
     pub chatgpt_base_url: Option<String>,
     pub experimental_instructions_file: Option<PathBuf>,
 }
+
+impl From<ConfigProfile> for codex_protocol::mcp_protocol::Profile {
+    fn from(config_profile: ConfigProfile) -> Self {
+        Self {
+            model: config_profile.model,
+            model_provider: config_profile.model_provider,
+            approval_policy: config_profile.approval_policy,
+            disable_response_storage: config_profile.disable_response_storage,
+            model_reasoning_effort: config_profile.model_reasoning_effort,
+            model_reasoning_summary: config_profile.model_reasoning_summary,
+            model_verbosity: config_profile.model_verbosity,
+            chatgpt_base_url: config_profile.chatgpt_base_url,
+        }
+    }
+}

codex-rs/core/src/config_types.rs

@@ -88,6 +88,17 @@ pub struct SandboxWorkspaceWrite {
     pub exclude_slash_tmp: bool,
 }
 
+impl From<SandboxWorkspaceWrite> for codex_protocol::mcp_protocol::SandboxSettings {
+    fn from(sandbox_workspace_write: SandboxWorkspaceWrite) -> Self {
+        Self {
+            writable_roots: sandbox_workspace_write.writable_roots,
+            network_access: Some(sandbox_workspace_write.network_access),
+            exclude_tmpdir_env_var: Some(sandbox_workspace_write.exclude_tmpdir_env_var),
+            exclude_slash_tmp: Some(sandbox_workspace_write.exclude_slash_tmp),
+        }
+    }
+}
+
 #[derive(Deserialize, Debug, Clone, PartialEq, Default)]
 #[serde(rename_all = "kebab-case")]
 pub enum ShellEnvironmentPolicyInherit {

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

@@ -45,7 +45,7 @@ use codex_protocol::mcp_protocol::ExecArbitraryCommandResponse;
 use codex_protocol::mcp_protocol::ExecCommandApprovalParams;
 use codex_protocol::mcp_protocol::ExecCommandApprovalResponse;
 use codex_protocol::mcp_protocol::ExecOneOffCommandParams;
-use codex_protocol::mcp_protocol::GetConfigTomlResponse;
+use codex_protocol::mcp_protocol::GetUserSavedConfigResponse;
 use codex_protocol::mcp_protocol::GitDiffToRemoteResponse;
 use codex_protocol::mcp_protocol::InputItem as WireInputItem;
 use codex_protocol::mcp_protocol::InterruptConversationParams;
@@ -61,6 +61,7 @@ use codex_protocol::mcp_protocol::SendUserMessageResponse;
 use codex_protocol::mcp_protocol::SendUserTurnParams;
 use codex_protocol::mcp_protocol::SendUserTurnResponse;
 use codex_protocol::mcp_protocol::ServerNotification;
+use codex_protocol::mcp_protocol::UserSavedConfig;
 use mcp_types::JSONRPCErrorError;
 use mcp_types::RequestId;
 use tokio::sync::Mutex;
@@ -153,8 +154,8 @@ impl CodexMessageProcessor {
             ClientRequest::GetAuthStatus { request_id, params } => {
                 self.get_auth_status(request_id, params).await;
             }
-            ClientRequest::GetConfigToml { request_id } => {
+            ClientRequest::GetUserSavedConfig { request_id } => {
-                self.get_config_toml(request_id).await;
+                self.get_user_saved_config(request_id).await;
             }
             ClientRequest::ExecOneOffCommand { request_id, params } => {
                 self.exec_one_off_command(request_id, params).await;
@@ -371,7 +372,7 @@ impl CodexMessageProcessor {
         self.outgoing.send_response(request_id, response).await;
     }
 
-    async fn get_config_toml(&self, request_id: RequestId) {
+    async fn get_user_saved_config(&self, request_id: RequestId) {
         let toml_value = match load_config_as_toml(&self.config.codex_home) {
             Ok(val) => val,
             Err(err) => {
@@ -398,32 +399,11 @@ impl CodexMessageProcessor {
             }
         };
 
-        let profiles: HashMap<String, codex_protocol::config_types::ConfigProfile> = cfg
+        let user_saved_config: UserSavedConfig = cfg.into();
-            .profiles
-            .into_iter()
-            .map(|(k, v)| {
-                (
-                    k,
-                    // Define this explicitly here to avoid the need to
-                    // implement `From<codex_core::config_profile::ConfigProfile>`
-                    // for the `ConfigProfile` type and introduce a dependency on codex_core
-                    codex_protocol::config_types::ConfigProfile {
-                        model: v.model,
-                        approval_policy: v.approval_policy,
-                        model_reasoning_effort: v.model_reasoning_effort,
-                    },
-                )
-            })
-            .collect();
 
-        let response = GetConfigTomlResponse {
+        let response = GetUserSavedConfigResponse {
-            approval_policy: cfg.approval_policy,
+            config: user_saved_config,
-            sandbox_mode: cfg.sandbox_mode,
-            model_reasoning_effort: cfg.model_reasoning_effort,
-            profile: cfg.profile,
-            profiles: Some(profiles),
         };
-
         self.outgoing.send_response(request_id, response).await;
     }
 

codex-rs/mcp-server/tests/common/mcp_process.rs

@@ -240,9 +240,9 @@ impl McpProcess {
         self.send_request("getAuthStatus", params).await
     }
 
-    /// Send a `getConfigToml` JSON-RPC request.
+    /// Send a `getUserSavedConfig` JSON-RPC request.
-    pub async fn send_get_config_toml_request(&mut self) -> anyhow::Result<i64> {
+    pub async fn send_get_user_saved_config_request(&mut self) -> anyhow::Result<i64> {
-        self.send_request("getConfigToml", None).await
+        self.send_request("getUserSavedConfig", None).await
     }
 
     /// Send a `loginChatGpt` JSON-RPC request.

codex-rs/mcp-server/tests/suite/config.rs

@@ -2,10 +2,15 @@ use std::collections::HashMap;
 use std::path::Path;
 
 use codex_core::protocol::AskForApproval;
-use codex_protocol::config_types::ConfigProfile;
 use codex_protocol::config_types::ReasoningEffort;
+use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode;
-use codex_protocol::mcp_protocol::GetConfigTomlResponse;
+use codex_protocol::config_types::Verbosity;
+use codex_protocol::mcp_protocol::GetUserSavedConfigResponse;
+use codex_protocol::mcp_protocol::Profile;
+use codex_protocol::mcp_protocol::SandboxSettings;
+use codex_protocol::mcp_protocol::Tools;
+use codex_protocol::mcp_protocol::UserSavedConfig;
 use mcp_test_support::McpProcess;
 use mcp_test_support::to_response;
 use mcp_types::JSONRPCResponse;
@@ -21,22 +26,39 @@ fn create_config_toml(codex_home: &Path) -> std::io::Result<()> {
     std::fs::write(
         config_toml,
         r#"
+model = "gpt-5"
 approval_policy = "on-request"
 sandbox_mode = "workspace-write"
+model_reasoning_summary = "detailed"
 model_reasoning_effort = "high"
+model_verbosity = "medium"
 profile = "test"
 
+[sandbox_workspace_write]
+writable_roots = ["/tmp"]
+network_access = true
+exclude_tmpdir_env_var = true
+exclude_slash_tmp = true
+
+[tools]
+web_search = false
+view_image = true
+
 [profiles.test]
 model = "gpt-4o"
 approval_policy = "on-request"
 model_reasoning_effort = "high"
 model_reasoning_summary = "detailed"
+model_verbosity = "medium"
+model_provider = "openai"
+disable_response_storage = false
+chatgpt_base_url = "https://api.chatgpt.com"
 "#,
     )
 }
 
-#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
-async fn get_config_toml_returns_subset() {
+async fn get_config_toml_parses_all_fields() {
     let codex_home = TempDir::new().unwrap_or_else(|e| panic!("create tempdir: {e}"));
     create_config_toml(codex_home.path()).expect("write config.toml");
 
@@ -49,32 +71,95 @@ async fn get_config_toml_returns_subset() {
         .expect("init failed");
 
     let request_id = mcp
-        .send_get_config_toml_request()
+        .send_get_user_saved_config_request()
         .await
-        .expect("send getConfigToml");
+        .expect("send getUserSavedConfig");
     let resp: JSONRPCResponse = timeout(
         DEFAULT_READ_TIMEOUT,
         mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
     )
     .await
-    .expect("getConfigToml timeout")
+    .expect("getUserSavedConfig timeout")
-    .expect("getConfigToml response");
+    .expect("getUserSavedConfig response");
 
-    let config: GetConfigTomlResponse = to_response(resp).expect("deserialize config");
+    let config: GetUserSavedConfigResponse = to_response(resp).expect("deserialize config");
-    let expected = GetConfigTomlResponse {
+    let expected = GetUserSavedConfigResponse {
-        approval_policy: Some(AskForApproval::OnRequest),
+        config: UserSavedConfig {
-        sandbox_mode: Some(SandboxMode::WorkspaceWrite),
+            approval_policy: Some(AskForApproval::OnRequest),
-        model_reasoning_effort: Some(ReasoningEffort::High),
+            sandbox_mode: Some(SandboxMode::WorkspaceWrite),
-        profile: Some("test".to_string()),
+            sandbox_settings: Some(SandboxSettings {
-        profiles: Some(HashMap::from([(
+                writable_roots: vec!["/tmp".into()],
-            "test".into(),
+                network_access: Some(true),
-            ConfigProfile {
+                exclude_tmpdir_env_var: Some(true),
-                model: Some("gpt-4o".into()),
+                exclude_slash_tmp: Some(true),
-                approval_policy: Some(AskForApproval::OnRequest),
+            }),
-                model_reasoning_effort: Some(ReasoningEffort::High),
+            model: Some("gpt-5".into()),
-            },
+            model_reasoning_effort: Some(ReasoningEffort::High),
-        )])),
+            model_reasoning_summary: Some(ReasoningSummary::Detailed),
+            model_verbosity: Some(Verbosity::Medium),
+            tools: Some(Tools {
+                web_search: Some(false),
+                view_image: Some(true),
+            }),
+            profile: Some("test".to_string()),
+            profiles: HashMap::from([(
+                "test".into(),
+                Profile {
+                    model: Some("gpt-4o".into()),
+                    approval_policy: Some(AskForApproval::OnRequest),
+                    model_reasoning_effort: Some(ReasoningEffort::High),
+                    model_reasoning_summary: Some(ReasoningSummary::Detailed),
+                    model_verbosity: Some(Verbosity::Medium),
+                    model_provider: Some("openai".into()),
+                    disable_response_storage: Some(false),
+                    chatgpt_base_url: Some("https://api.chatgpt.com".into()),
+                },
+            )]),
+        },
     };
 
-    assert_eq!(expected, config);
+    assert_eq!(config, expected);
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn get_config_toml_empty() {
+    let codex_home = TempDir::new().unwrap_or_else(|e| panic!("create tempdir: {e}"));
+
+    let mut mcp = McpProcess::new(codex_home.path())
+        .await
+        .expect("spawn mcp process");
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize())
+        .await
+        .expect("init timeout")
+        .expect("init failed");
+
+    let request_id = mcp
+        .send_get_user_saved_config_request()
+        .await
+        .expect("send getUserSavedConfig");
+    let resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
+    )
+    .await
+    .expect("getUserSavedConfig timeout")
+    .expect("getUserSavedConfig response");
+
+    let config: GetUserSavedConfigResponse = to_response(resp).expect("deserialize config");
+    let expected = GetUserSavedConfigResponse {
+        config: UserSavedConfig {
+            approval_policy: None,
+            sandbox_mode: None,
+            sandbox_settings: None,
+            model: None,
+            model_reasoning_effort: None,
+            model_reasoning_summary: None,
+            model_verbosity: None,
+            tools: None,
+            profile: None,
+            profiles: HashMap::new(),
+        },
+    };
+
+    assert_eq!(config, expected);
 }

codex-rs/protocol-ts/src/lib.rs

@@ -46,6 +46,7 @@ pub fn generate_ts(out_dir: &Path, prettier: Option<&Path>) -> Result<()> {
     codex_protocol::mcp_protocol::ApplyPatchApprovalResponse::export_all_to(out_dir)?;
     codex_protocol::mcp_protocol::ExecCommandApprovalParams::export_all_to(out_dir)?;
     codex_protocol::mcp_protocol::ExecCommandApprovalResponse::export_all_to(out_dir)?;
+    codex_protocol::mcp_protocol::GetUserSavedConfigResponse::export_all_to(out_dir)?;
     codex_protocol::mcp_protocol::ServerNotification::export_all_to(out_dir)?;
 
     generate_index_ts(out_dir)?;

codex-rs/protocol/src/config_types.rs

@@ -4,8 +4,6 @@ use strum_macros::Display;
 use strum_macros::EnumIter;
 use ts_rs::TS;
 
-use crate::protocol::AskForApproval;
-
 /// See https://platform.openai.com/docs/guides/reasoning?api-mode=responses#get-started-with-reasoning
 #[derive(
     Debug, Serialize, Deserialize, Default, Clone, Copy, PartialEq, Eq, Display, TS, EnumIter,
@@ -37,7 +35,7 @@ pub enum ReasoningSummary {
 
 /// Controls output length/detail on GPT-5 models via the Responses API.
 /// Serialized with lowercase values to match the OpenAI API.
-#[derive(Debug, Serialize, Deserialize, Default, Clone, Copy, PartialEq, Eq, Display)]
+#[derive(Debug, Serialize, Deserialize, Default, Clone, Copy, PartialEq, Eq, Display, TS)]
 #[serde(rename_all = "lowercase")]
 #[strum(serialize_all = "lowercase")]
 pub enum Verbosity {
@@ -61,13 +59,3 @@ pub enum SandboxMode {
     #[serde(rename = "danger-full-access")]
     DangerFullAccess,
 }
-
-/// Collection of common configuration options that a user can define as a unit
-/// in `config.toml`. Currently only a subset of the fields are supported.
-#[derive(Deserialize, Debug, Clone, PartialEq, Serialize, TS)]
-#[serde(rename_all = "camelCase")]
-pub struct ConfigProfile {
-    pub model: Option<String>,
-    pub approval_policy: Option<AskForApproval>,
-    pub model_reasoning_effort: Option<ReasoningEffort>,
-}

codex-rs/protocol/src/mcp_protocol.rs

@@ -2,10 +2,10 @@ use std::collections::HashMap;
 use std::fmt::Display;
 use std::path::PathBuf;
 
-use crate::config_types::ConfigProfile;
 use crate::config_types::ReasoningEffort;
 use crate::config_types::ReasoningSummary;
 use crate::config_types::SandboxMode;
+use crate::config_types::Verbosity;
 use crate::protocol::AskForApproval;
 use crate::protocol::FileChange;
 use crate::protocol::ReviewDecision;
@@ -102,7 +102,7 @@ pub enum ClientRequest {
         request_id: RequestId,
         params: GetAuthStatusParams,
     },
-    GetConfigToml {
+    GetUserSavedConfig {
         #[serde(rename = "id")]
         request_id: RequestId,
     },
@@ -260,22 +260,82 @@ pub struct GetAuthStatusResponse {
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]
 #[serde(rename_all = "camelCase")]
-pub struct GetConfigTomlResponse {
+pub struct GetUserSavedConfigResponse {
+    pub config: UserSavedConfig,
+}
+
+/// UserSavedConfig contains a subset of the config. It is meant to expose mcp
+/// client-configurable settings that can be specified in the NewConversation
+/// and SendUserTurn requests.
+#[derive(Deserialize, Debug, Clone, PartialEq, Serialize, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct UserSavedConfig {
     /// Approvals
     #[serde(skip_serializing_if = "Option::is_none")]
     pub approval_policy: Option<AskForApproval>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub sandbox_mode: Option<SandboxMode>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub sandbox_settings: Option<SandboxSettings>,
 
-    /// Relevant model configuration
+    /// Model-specific configuration
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub model: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub model_reasoning_effort: Option<ReasoningEffort>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub model_reasoning_summary: Option<ReasoningSummary>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub model_verbosity: Option<Verbosity>,
+
+    /// Tools
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tools: Option<Tools>,
 
     /// Profiles
     #[serde(skip_serializing_if = "Option::is_none")]
     pub profile: Option<String>,
+    #[serde(default)]
+    pub profiles: HashMap<String, Profile>,
+}
+
+/// MCP representation of a [`codex_core::config_profile::ConfigProfile`].
+#[derive(Deserialize, Debug, Clone, PartialEq, Serialize, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct Profile {
+    pub model: Option<String>,
+    /// The key in the `model_providers` map identifying the
+    /// [`ModelProviderInfo`] to use.
+    pub model_provider: Option<String>,
+    pub approval_policy: Option<AskForApproval>,
+    pub disable_response_storage: Option<bool>,
+    pub model_reasoning_effort: Option<ReasoningEffort>,
+    pub model_reasoning_summary: Option<ReasoningSummary>,
+    pub model_verbosity: Option<Verbosity>,
+    pub chatgpt_base_url: Option<String>,
+}
+/// MCP representation of a [`codex_core::config::ToolsToml`].
+#[derive(Deserialize, Debug, Clone, PartialEq, Serialize, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct Tools {
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub profiles: Option<HashMap<String, ConfigProfile>>,
+    pub web_search: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub view_image: Option<bool>,
+}
+
+/// MCP representation of a [`codex_core::config_types::SandboxWorkspaceWrite`].
+#[derive(Deserialize, Debug, Clone, PartialEq, Serialize, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct SandboxSettings {
+    #[serde(default)]
+    pub writable_roots: Vec<PathBuf>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub network_access: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub exclude_tmpdir_env_var: Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub exclude_slash_tmp: Option<bool>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]