[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 {