Extract MCP into codex-mcp crate (#15919)

- Split MCP runtime/server code out of `codex-core` into the new
`codex-mcp` crate. New/moved public structs/types include `McpConfig`,
`McpConnectionManager`, `ToolInfo`, `ToolPluginProvenance`,
`CodexAppsToolsCacheKey`, and the `McpManager` API
(`codex_mcp::mcp::McpManager` plus the `codex_core::mcp::McpManager`
wrapper/shim). New/moved functions include `with_codex_apps_mcp`,
`configured_mcp_servers`, `effective_mcp_servers`,
`collect_mcp_snapshot`, `collect_mcp_snapshot_from_manager`,
`qualified_mcp_tool_name_prefix`, and the MCP auth/skill-dependency
helpers. Why: this creates a focused MCP crate boundary and shrinks
`codex-core` without forcing every consumer to migrate in the same PR.

- Move MCP server config schema and persistence into `codex-config`.
New/moved structs/enums include `AppToolApproval`,
`McpServerToolConfig`, `McpServerConfig`, `RawMcpServerConfig`,
`McpServerTransportConfig`, `McpServerDisabledReason`, and
`codex_config::ConfigEditsBuilder`. New/moved functions include
`load_global_mcp_servers` and
`ConfigEditsBuilder::replace_mcp_servers`/`apply`. Why: MCP TOML
parsing/editing is config ownership, and this keeps config
validation/round-tripping (including per-tool approval overrides and
inline bearer-token rejection) in the config crate instead of
`codex-core`.

- Rewire `codex-core`, app-server, and plugin call sites onto the new
crates. Updated `Config::to_mcp_config(&self, plugins_manager)`,
`codex-rs/core/src/mcp.rs`, `codex-rs/core/src/connectors.rs`,
`codex-rs/core/src/codex.rs`,
`CodexMessageProcessor::list_mcp_server_status_task`, and
`utils/plugins/src/mcp_connector.rs` to build/pass the new MCP
config/runtime types. Why: plugin-provided MCP servers still merge with
user-configured servers, and runtime auth (`CodexAuth`) is threaded into
`with_codex_apps_mcp` / `collect_mcp_snapshot` explicitly so `McpConfig`
stays config-only.

codex-rs/codex-mcp/src/mcp/mod.rs

@@ -0,0 +1,476 @@
+pub mod auth;
+mod skill_dependencies;
+pub use skill_dependencies::canonical_mcp_server_key;
+pub use skill_dependencies::collect_missing_mcp_dependencies;
+
+use std::collections::HashMap;
+use std::env;
+use std::path::PathBuf;
+use std::time::Duration;
+
+use async_channel::unbounded;
+use codex_config::Constrained;
+use codex_config::McpServerConfig;
+use codex_config::McpServerTransportConfig;
+use codex_login::CodexAuth;
+use codex_plugin::PluginCapabilitySummary;
+use codex_protocol::mcp::Resource;
+use codex_protocol::mcp::ResourceTemplate;
+use codex_protocol::mcp::Tool;
+use codex_protocol::protocol::AskForApproval;
+use codex_protocol::protocol::McpListToolsResponseEvent;
+use codex_protocol::protocol::SandboxPolicy;
+use codex_rmcp_client::OAuthCredentialsStoreMode;
+use serde_json::Value;
+
+use crate::mcp::auth::compute_auth_statuses;
+use crate::mcp_connection_manager::McpConnectionManager;
+use crate::mcp_connection_manager::SandboxState;
+use crate::mcp_connection_manager::codex_apps_tools_cache_key;
+pub type McpManager = McpConnectionManager;
+
+const MCP_TOOL_NAME_PREFIX: &str = "mcp";
+const MCP_TOOL_NAME_DELIMITER: &str = "__";
+pub const CODEX_APPS_MCP_SERVER_NAME: &str = "codex_apps";
+const CODEX_CONNECTORS_TOKEN_ENV_VAR: &str = "CODEX_CONNECTORS_TOKEN";
+
+/// The Responses API requires tool names to match `^[a-zA-Z0-9_-]+$`.
+/// MCP server/tool names are user-controlled, so sanitize the fully-qualified
+/// name we expose to the model by replacing any disallowed character with `_`.
+pub(crate) fn sanitize_responses_api_tool_name(name: &str) -> String {
+    let mut sanitized = String::with_capacity(name.len());
+    for c in name.chars() {
+        if c.is_ascii_alphanumeric() || c == '_' {
+            sanitized.push(c);
+        } else {
+            sanitized.push('_');
+        }
+    }
+
+    if sanitized.is_empty() {
+        "_".to_string()
+    } else {
+        sanitized
+    }
+}
+
+pub fn qualified_mcp_tool_name_prefix(server_name: &str) -> String {
+    sanitize_responses_api_tool_name(&format!(
+        "{MCP_TOOL_NAME_PREFIX}{MCP_TOOL_NAME_DELIMITER}{server_name}{MCP_TOOL_NAME_DELIMITER}"
+    ))
+}
+
+/// MCP runtime settings derived from `codex_core::config::Config`.
+///
+/// This struct should contain only long-lived configuration values that the
+/// `codex-mcp` crate needs to construct server transports, enforce MCP
+/// approval/sandbox policy, locate OAuth state, and merge plugin-provided MCP
+/// servers. Request-scoped or auth-scoped state should not be stored here;
+/// thread those values explicitly into runtime entry points such as
+/// [`with_codex_apps_mcp`] and [`collect_mcp_snapshot`] so config objects do
+/// not go stale when auth changes.
+#[derive(Debug, Clone)]
+pub struct McpConfig {
+    /// Base URL for ChatGPT-hosted app MCP servers, copied from the root config.
+    pub chatgpt_base_url: String,
+    /// Codex home directory used for MCP OAuth state and app-tool cache files.
+    pub codex_home: PathBuf,
+    /// Preferred credential store for MCP OAuth tokens.
+    pub mcp_oauth_credentials_store_mode: OAuthCredentialsStoreMode,
+    /// Optional fixed localhost callback port for MCP OAuth login.
+    pub mcp_oauth_callback_port: Option<u16>,
+    /// Optional OAuth redirect URI override for MCP login.
+    pub mcp_oauth_callback_url: Option<String>,
+    /// Whether skill MCP dependency installation prompts are enabled.
+    pub skill_mcp_dependency_install_enabled: bool,
+    /// Approval policy used for MCP tool calls and MCP elicitation requests.
+    pub approval_policy: Constrained<AskForApproval>,
+    /// Optional path to `codex-linux-sandbox` for sandboxed MCP tool execution.
+    pub codex_linux_sandbox_exe: Option<PathBuf>,
+    /// Whether to use legacy Landlock behavior in the MCP sandbox state.
+    pub use_legacy_landlock: bool,
+    /// Whether the app MCP integration is enabled by config.
+    ///
+    /// ChatGPT auth is checked separately at runtime before the built-in apps
+    /// MCP server is added.
+    pub apps_enabled: bool,
+    /// User-configured and plugin-provided MCP servers keyed by server name.
+    pub configured_mcp_servers: HashMap<String, McpServerConfig>,
+    /// Plugin metadata used to attribute MCP tools/connectors to plugin display names.
+    pub plugin_capability_summaries: Vec<PluginCapabilitySummary>,
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct ToolPluginProvenance {
+    plugin_display_names_by_connector_id: HashMap<String, Vec<String>>,
+    plugin_display_names_by_mcp_server_name: HashMap<String, Vec<String>>,
+}
+
+impl ToolPluginProvenance {
+    pub fn plugin_display_names_for_connector_id(&self, connector_id: &str) -> &[String] {
+        self.plugin_display_names_by_connector_id
+            .get(connector_id)
+            .map(Vec::as_slice)
+            .unwrap_or(&[])
+    }
+
+    pub fn plugin_display_names_for_mcp_server_name(&self, server_name: &str) -> &[String] {
+        self.plugin_display_names_by_mcp_server_name
+            .get(server_name)
+            .map(Vec::as_slice)
+            .unwrap_or(&[])
+    }
+
+    fn from_capability_summaries(capability_summaries: &[PluginCapabilitySummary]) -> Self {
+        let mut tool_plugin_provenance = Self::default();
+        for plugin in capability_summaries {
+            for connector_id in &plugin.app_connector_ids {
+                tool_plugin_provenance
+                    .plugin_display_names_by_connector_id
+                    .entry(connector_id.0.clone())
+                    .or_default()
+                    .push(plugin.display_name.clone());
+            }
+
+            for server_name in &plugin.mcp_server_names {
+                tool_plugin_provenance
+                    .plugin_display_names_by_mcp_server_name
+                    .entry(server_name.clone())
+                    .or_default()
+                    .push(plugin.display_name.clone());
+            }
+        }
+
+        for plugin_names in tool_plugin_provenance
+            .plugin_display_names_by_connector_id
+            .values_mut()
+            .chain(
+                tool_plugin_provenance
+                    .plugin_display_names_by_mcp_server_name
+                    .values_mut(),
+            )
+        {
+            plugin_names.sort_unstable();
+            plugin_names.dedup();
+        }
+
+        tool_plugin_provenance
+    }
+}
+
+fn codex_apps_mcp_bearer_token_env_var() -> Option<String> {
+    match env::var(CODEX_CONNECTORS_TOKEN_ENV_VAR) {
+        Ok(value) if !value.trim().is_empty() => Some(CODEX_CONNECTORS_TOKEN_ENV_VAR.to_string()),
+        Ok(_) => None,
+        Err(env::VarError::NotPresent) => None,
+        Err(env::VarError::NotUnicode(_)) => Some(CODEX_CONNECTORS_TOKEN_ENV_VAR.to_string()),
+    }
+}
+
+fn codex_apps_mcp_bearer_token(auth: Option<&CodexAuth>) -> Option<String> {
+    let token = auth.and_then(|auth| auth.get_token().ok())?;
+    let token = token.trim();
+    if token.is_empty() {
+        None
+    } else {
+        Some(token.to_string())
+    }
+}
+
+fn codex_apps_mcp_http_headers(auth: Option<&CodexAuth>) -> Option<HashMap<String, String>> {
+    let mut headers = HashMap::new();
+    if let Some(token) = codex_apps_mcp_bearer_token(auth) {
+        headers.insert("Authorization".to_string(), format!("Bearer {token}"));
+    }
+    if let Some(account_id) = auth.and_then(CodexAuth::get_account_id) {
+        headers.insert("ChatGPT-Account-ID".to_string(), account_id);
+    }
+    if headers.is_empty() {
+        None
+    } else {
+        Some(headers)
+    }
+}
+
+fn normalize_codex_apps_base_url(base_url: &str) -> String {
+    let mut base_url = base_url.trim_end_matches('/').to_string();
+    if (base_url.starts_with("https://chatgpt.com")
+        || base_url.starts_with("https://chat.openai.com"))
+        && !base_url.contains("/backend-api")
+    {
+        base_url = format!("{base_url}/backend-api");
+    }
+    base_url
+}
+
+fn codex_apps_mcp_url_for_base_url(base_url: &str) -> String {
+    let base_url = normalize_codex_apps_base_url(base_url);
+    if base_url.contains("/backend-api") {
+        format!("{base_url}/wham/apps")
+    } else if base_url.contains("/api/codex") {
+        format!("{base_url}/apps")
+    } else {
+        format!("{base_url}/api/codex/apps")
+    }
+}
+
+pub(crate) fn codex_apps_mcp_url(config: &McpConfig) -> String {
+    codex_apps_mcp_url_for_base_url(&config.chatgpt_base_url)
+}
+
+fn codex_apps_mcp_server_config(config: &McpConfig, auth: Option<&CodexAuth>) -> McpServerConfig {
+    let bearer_token_env_var = codex_apps_mcp_bearer_token_env_var();
+    let http_headers = if bearer_token_env_var.is_some() {
+        None
+    } else {
+        codex_apps_mcp_http_headers(auth)
+    };
+    let url = codex_apps_mcp_url(config);
+
+    McpServerConfig {
+        transport: McpServerTransportConfig::StreamableHttp {
+            url,
+            bearer_token_env_var,
+            http_headers,
+            env_http_headers: None,
+        },
+        enabled: true,
+        required: false,
+        disabled_reason: None,
+        startup_timeout_sec: Some(Duration::from_secs(30)),
+        tool_timeout_sec: None,
+        enabled_tools: None,
+        disabled_tools: None,
+        scopes: None,
+        oauth_resource: None,
+        tools: HashMap::new(),
+    }
+}
+
+pub fn with_codex_apps_mcp(
+    mut servers: HashMap<String, McpServerConfig>,
+    auth: Option<&CodexAuth>,
+    config: &McpConfig,
+) -> HashMap<String, McpServerConfig> {
+    if config.apps_enabled && auth.is_some_and(CodexAuth::is_chatgpt_auth) {
+        servers.insert(
+            CODEX_APPS_MCP_SERVER_NAME.to_string(),
+            codex_apps_mcp_server_config(config, auth),
+        );
+    } else {
+        servers.remove(CODEX_APPS_MCP_SERVER_NAME);
+    }
+    servers
+}
+
+pub fn configured_mcp_servers(config: &McpConfig) -> HashMap<String, McpServerConfig> {
+    config.configured_mcp_servers.clone()
+}
+
+pub fn effective_mcp_servers(
+    config: &McpConfig,
+    auth: Option<&CodexAuth>,
+) -> HashMap<String, McpServerConfig> {
+    let servers = configured_mcp_servers(config);
+    with_codex_apps_mcp(servers, auth, config)
+}
+
+pub fn tool_plugin_provenance(config: &McpConfig) -> ToolPluginProvenance {
+    ToolPluginProvenance::from_capability_summaries(&config.plugin_capability_summaries)
+}
+
+pub async fn collect_mcp_snapshot(
+    config: &McpConfig,
+    auth: Option<&CodexAuth>,
+    submit_id: String,
+) -> McpListToolsResponseEvent {
+    let mcp_servers = effective_mcp_servers(config, auth);
+    let tool_plugin_provenance = tool_plugin_provenance(config);
+    if mcp_servers.is_empty() {
+        return McpListToolsResponseEvent {
+            tools: HashMap::new(),
+            resources: HashMap::new(),
+            resource_templates: HashMap::new(),
+            auth_statuses: HashMap::new(),
+        };
+    }
+
+    let auth_status_entries =
+        compute_auth_statuses(mcp_servers.iter(), config.mcp_oauth_credentials_store_mode).await;
+
+    let (tx_event, rx_event) = unbounded();
+    drop(rx_event);
+
+    // Use ReadOnly sandbox policy for MCP snapshot collection (safest default)
+    let sandbox_state = SandboxState {
+        sandbox_policy: SandboxPolicy::new_read_only_policy(),
+        codex_linux_sandbox_exe: config.codex_linux_sandbox_exe.clone(),
+        sandbox_cwd: env::current_dir().unwrap_or_else(|_| PathBuf::from("/")),
+        use_legacy_landlock: config.use_legacy_landlock,
+    };
+
+    let (mcp_connection_manager, cancel_token) = McpConnectionManager::new(
+        &mcp_servers,
+        config.mcp_oauth_credentials_store_mode,
+        auth_status_entries.clone(),
+        &config.approval_policy,
+        submit_id,
+        tx_event,
+        sandbox_state,
+        config.codex_home.clone(),
+        codex_apps_tools_cache_key(auth),
+        tool_plugin_provenance,
+    )
+    .await;
+
+    let snapshot =
+        collect_mcp_snapshot_from_manager(&mcp_connection_manager, auth_status_entries).await;
+
+    cancel_token.cancel();
+
+    snapshot
+}
+
+pub fn split_qualified_tool_name(qualified_name: &str) -> Option<(String, String)> {
+    let mut parts = qualified_name.split(MCP_TOOL_NAME_DELIMITER);
+    let prefix = parts.next()?;
+    if prefix != MCP_TOOL_NAME_PREFIX {
+        return None;
+    }
+    let server_name = parts.next()?;
+    let tool_name: String = parts.collect::<Vec<_>>().join(MCP_TOOL_NAME_DELIMITER);
+    if tool_name.is_empty() {
+        return None;
+    }
+    Some((server_name.to_string(), tool_name))
+}
+
+pub fn group_tools_by_server(
+    tools: &HashMap<String, Tool>,
+) -> HashMap<String, HashMap<String, Tool>> {
+    let mut grouped = HashMap::new();
+    for (qualified_name, tool) in tools {
+        if let Some((server_name, tool_name)) = split_qualified_tool_name(qualified_name) {
+            grouped
+                .entry(server_name)
+                .or_insert_with(HashMap::new)
+                .insert(tool_name, tool.clone());
+        }
+    }
+    grouped
+}
+
+pub async fn collect_mcp_snapshot_from_manager(
+    mcp_connection_manager: &McpConnectionManager,
+    auth_status_entries: HashMap<String, crate::mcp::auth::McpAuthStatusEntry>,
+) -> McpListToolsResponseEvent {
+    let (tools, resources, resource_templates) = tokio::join!(
+        mcp_connection_manager.list_all_tools(),
+        mcp_connection_manager.list_all_resources(),
+        mcp_connection_manager.list_all_resource_templates(),
+    );
+
+    let auth_statuses = auth_status_entries
+        .iter()
+        .map(|(name, entry)| (name.clone(), entry.auth_status))
+        .collect::<HashMap<_, _>>();
+
+    let tools = tools
+        .into_iter()
+        .filter_map(|(name, tool)| match serde_json::to_value(tool.tool) {
+            Ok(value) => match Tool::from_mcp_value(value) {
+                Ok(tool) => Some((name, tool)),
+                Err(err) => {
+                    tracing::warn!("Failed to convert MCP tool '{name}': {err}");
+                    None
+                }
+            },
+            Err(err) => {
+                tracing::warn!("Failed to serialize MCP tool '{name}': {err}");
+                None
+            }
+        })
+        .collect::<HashMap<_, _>>();
+
+    let resources = resources
+        .into_iter()
+        .map(|(name, resources)| {
+            let resources = resources
+                .into_iter()
+                .filter_map(|resource| match serde_json::to_value(resource) {
+                    Ok(value) => match Resource::from_mcp_value(value.clone()) {
+                        Ok(resource) => Some(resource),
+                        Err(err) => {
+                            let (uri, resource_name) = match value {
+                                Value::Object(obj) => (
+                                    obj.get("uri")
+                                        .and_then(|v| v.as_str().map(ToString::to_string)),
+                                    obj.get("name")
+                                        .and_then(|v| v.as_str().map(ToString::to_string)),
+                                ),
+                                _ => (None, None),
+                            };
+
+                            tracing::warn!(
+                                "Failed to convert MCP resource (uri={uri:?}, name={resource_name:?}): {err}"
+                            );
+                            None
+                        }
+                    },
+                    Err(err) => {
+                        tracing::warn!("Failed to serialize MCP resource: {err}");
+                        None
+                    }
+                })
+                .collect::<Vec<_>>();
+            (name, resources)
+        })
+        .collect::<HashMap<_, _>>();
+
+    let resource_templates = resource_templates
+        .into_iter()
+        .map(|(name, templates)| {
+            let templates = templates
+                .into_iter()
+                .filter_map(|template| match serde_json::to_value(template) {
+                    Ok(value) => match ResourceTemplate::from_mcp_value(value.clone()) {
+                        Ok(template) => Some(template),
+                        Err(err) => {
+                            let (uri_template, template_name) = match value {
+                                Value::Object(obj) => (
+                                    obj.get("uriTemplate")
+                                        .or_else(|| obj.get("uri_template"))
+                                        .and_then(|v| v.as_str().map(ToString::to_string)),
+                                    obj.get("name")
+                                        .and_then(|v| v.as_str().map(ToString::to_string)),
+                                ),
+                                _ => (None, None),
+                            };
+
+                            tracing::warn!(
+                                "Failed to convert MCP resource template (uri_template={uri_template:?}, name={template_name:?}): {err}"
+                            );
+                            None
+                        }
+                    },
+                    Err(err) => {
+                        tracing::warn!("Failed to serialize MCP resource template: {err}");
+                        None
+                    }
+                })
+                .collect::<Vec<_>>();
+            (name, templates)
+        })
+        .collect::<HashMap<_, _>>();
+
+    McpListToolsResponseEvent {
+        tools,
+        resources,
+        resource_templates,
+        auth_statuses,
+    }
+}
+
+#[cfg(test)]
+#[path = "mod_tests.rs"]
+mod tests;