openai/codex · error · anyhow::Error

MCP server URL `{server_url}` must include a host

Error message

MCP server URL `{server_url}` must include a host

What it means

Error "MCP server URL `{server_url}` must include a host" thrown in openai/codex.

Source

Thrown at codex-rs/rmcp-client/src/perform_oauth_login.rs:458

}

fn resolve_redirect_uri(server: &Server, callback_url: Option<&str>) -> Result<String> {
    let Some(callback_url) = callback_url else {
        return local_redirect_uri(server);
    };
    Url::parse(callback_url)
        .with_context(|| format!("invalid MCP OAuth callback URL `{callback_url}`"))?;
    Ok(callback_url.to_string())
}

fn callback_id_from_server_url(server_url: &str) -> Result<String> {
    // Native Codex callback IDs intentionally hash the complete MCP URL (minus its fragment)
    // with SHA-256. Python connector callback IDs use SHAKE-256 over the origin and are distinct.
    let mut parsed =
        Url::parse(server_url).with_context(|| format!("invalid MCP server URL `{server_url}`"))?;
    parsed
        .host_str()
        .ok_or_else(|| anyhow!("MCP server URL `{server_url}` must include a host"))?;
    parsed.set_fragment(None);

    let digest = Sha256::digest(parsed.as_str().as_bytes());
    Ok(URL_SAFE_NO_PAD.encode(&digest[..9]))
}

fn append_callback_id_to_redirect_uri(redirect_uri: &str, callback_id: &str) -> Result<String> {
    let mut parsed = Url::parse(redirect_uri)
        .with_context(|| format!("invalid redirect URI `{redirect_uri}`"))?;
    let path = parsed.path();
    let new_path = if path.ends_with('/') {
        format!("{path}{callback_id}")
    } else {
        format!("{path}/{callback_id}")
    };
    parsed.set_path(&new_path);
    Ok(parsed.to_string())
}

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/rmcp-client/src/perform_oauth_login.rs:458 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/93cf98c8826bd0a4. Report an issue: GitHub.