codex/codex-rs/codex-mcp/src/mcp/skill_dependencies.rs

use std::collections::HashMap;
use std::collections::HashSet;

use codex_config::McpServerConfig;
use codex_config::McpServerTransportConfig;
use codex_protocol::protocol::SkillMetadata;
use codex_protocol::protocol::SkillToolDependency;
use tracing::warn;

pub fn collect_missing_mcp_dependencies(
    mentioned_skills: &[SkillMetadata],
    installed: &HashMap<String, McpServerConfig>,
) -> HashMap<String, McpServerConfig> {
    let mut missing = HashMap::new();
    let installed_keys: HashSet<String> = installed
        .iter()
        .map(|(name, config)| canonical_mcp_server_key(name, config))
        .collect();
    let mut seen_canonical_keys = HashSet::new();

    for skill in mentioned_skills {
        let Some(dependencies) = skill.dependencies.as_ref() else {
            continue;
        };

        for tool in &dependencies.tools {
            if !tool.r#type.eq_ignore_ascii_case("mcp") {
                continue;
            }
            let dependency_key = match canonical_mcp_dependency_key(tool) {
                Ok(key) => key,
                Err(err) => {
                    let dependency = tool.value.as_str();
                    let skill_name = skill.name.as_str();
                    warn!(
                        "unable to auto-install MCP dependency {dependency} for skill {skill_name}: {err}",
                    );
                    continue;
                }
            };
            if installed_keys.contains(&dependency_key)
                || seen_canonical_keys.contains(&dependency_key)
            {
                continue;
            }

            let config = match mcp_dependency_to_server_config(tool) {
                Ok(config) => config,
                Err(err) => {
                    let dependency = dependency_key.as_str();
                    let skill_name = skill.name.as_str();
                    warn!(
                        "unable to auto-install MCP dependency {dependency} for skill {skill_name}: {err}",
                    );
                    continue;
                }
            };

            missing.insert(tool.value.clone(), config);
            seen_canonical_keys.insert(dependency_key);
        }
    }

    missing
}

fn canonical_mcp_key(transport: &str, identifier: &str, fallback: &str) -> String {
    let identifier = identifier.trim();
    if identifier.is_empty() {
        fallback.to_string()
    } else {
        format!("mcp__{transport}__{identifier}")
    }
}

pub fn canonical_mcp_server_key(name: &str, config: &McpServerConfig) -> String {
    match &config.transport {
        McpServerTransportConfig::Stdio { command, .. } => {
            canonical_mcp_key("stdio", command, name)
        }
        McpServerTransportConfig::StreamableHttp { url, .. } => {
            canonical_mcp_key("streamable_http", url, name)
        }
    }
}

fn canonical_mcp_dependency_key(dependency: &SkillToolDependency) -> Result<String, String> {
    let transport = dependency.transport.as_deref().unwrap_or("streamable_http");
    if transport.eq_ignore_ascii_case("streamable_http") {
        let url = dependency
            .url
            .as_ref()
            .ok_or_else(|| "missing url for streamable_http dependency".to_string())?;
        return Ok(canonical_mcp_key("streamable_http", url, &dependency.value));
    }
    if transport.eq_ignore_ascii_case("stdio") {
        let command = dependency
            .command
            .as_ref()
            .ok_or_else(|| "missing command for stdio dependency".to_string())?;
        return Ok(canonical_mcp_key("stdio", command, &dependency.value));
    }
    Err(format!("unsupported transport {transport}"))
}

fn mcp_dependency_to_server_config(
    dependency: &SkillToolDependency,
) -> Result<McpServerConfig, String> {
    let transport = dependency.transport.as_deref().unwrap_or("streamable_http");
    if transport.eq_ignore_ascii_case("streamable_http") {
        let url = dependency
            .url
            .as_ref()
            .ok_or_else(|| "missing url for streamable_http dependency".to_string())?;
        return Ok(McpServerConfig {
            transport: McpServerTransportConfig::StreamableHttp {
                url: url.clone(),
                bearer_token_env_var: None,
                http_headers: None,
                env_http_headers: None,
            },
            enabled: true,
            required: false,
            supports_parallel_tool_calls: false,
            disabled_reason: None,
            startup_timeout_sec: None,
            tool_timeout_sec: None,
            enabled_tools: None,
            disabled_tools: None,
            scopes: None,
            oauth_resource: None,
            tools: HashMap::new(),
        });
    }

    if transport.eq_ignore_ascii_case("stdio") {
        let command = dependency
            .command
            .as_ref()
            .ok_or_else(|| "missing command for stdio dependency".to_string())?;
        return Ok(McpServerConfig {
            transport: McpServerTransportConfig::Stdio {
                command: command.clone(),
                args: Vec::new(),
                env: None,
                env_vars: Vec::new(),
                cwd: None,
            },
            enabled: true,
            required: false,
            supports_parallel_tool_calls: false,
            disabled_reason: None,
            startup_timeout_sec: None,
            tool_timeout_sec: None,
            enabled_tools: None,
            disabled_tools: None,
            scopes: None,
            oauth_resource: None,
            tools: HashMap::new(),
        });
    }

    Err(format!("unsupported transport {transport}"))
}

#[cfg(test)]
#[path = "skill_dependencies_tests.rs"]
mod tests;