Struct McpEnv 

pub struct McpEnv {
    pub config_path: PathBuf,
    pub store_path: PathBuf,
    pub opener: BrowserOpener,
    pub now: u64,
    pub tools_dir: Option<PathBuf>,
    pub credential_store: Option<Box<dyn CredentialStore>>,
    pub allow_env_vars: Vec<String>,
}

Seams the real I/O of lev mcp depends on, injected so the command logic is unit-testable without a browser, real config, or the real home directory.

Fields

config_path: PathBuf

Path to the config file to read and rewrite.

store_path: PathBuf

Path to the OAuth token store.

opener: BrowserOpener

How to open the browser during a login.

now: u64

Current Unix time, for token-expiry math.

tools_dir: Option<PathBuf>

The global Rhai script-tools directory (<leviath-home>/tools/). lev mcp list also surfaces these tools (labeled script) so the listing covers every external tool provider, not only MCP servers. None disables the script scan (used by tests that only care about servers).

credential_store: Option<Box<dyn CredentialStore>>

Where OAuth grants are kept, already resolved. lev mcp login writes a refresh token, so it has to write it where the user asked for it to be kept.

Resolved by the caller rather than here, and before any subcommand runs: a keychain that was asked for but cannot be reached has to fail the command outright, because falling back to the file would put a refresh token on disk that the user asked to keep out of it. Doing that once at the edge also means these code paths carry no error arm that only an unreachable keychain could take.

allow_env_vars: Vec<String>

[security] allow_env_vars: which credential-shaped variables an MCP server’s ${VAR} headers may interpolate.