[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/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)]