Hmbown/CodeWhale · error · anyhow::Error

Provide either --command or --url for `mcp add`.

Error message

Provide either --command or --url for `mcp add`.

What it means

`codewhale mcp add` requires the MCP server to be defined either as a local command (--command) or a remote URL (--url). If both are absent, the configuration would be meaningless, so the CLI bails with this validation error.

Solutions

1. Add `--command <cmd> [args...]` for a stdio MCP server
2. Add `--url <https://...>` for a remote (SSE) MCP server
3. Re-check the intended server config and pass exactly one of the two

Example fix

// before
codewhale mcp add myserver
// after
codewhale mcp add myserver --command npx -- some-mcp-server

if command.is_none() && url.is_none() {
    eprintln!("mcp add needs --command or --url");
    std::process::exit(2);
}

When it happens

Trigger: Running `codewhale mcp add <name>` (with only a name and possibly env/scopes) without --command or --url.

Common situations: Copy-pasting an add command from docs and dropping the flags; assuming a name alone is enough; writing a script that builds the command conditionally and skips both options.

Understand the failure class

Background: "--flag is required" and "must specify" CLI errors: how missing-required-flag validation works and how to fix it — this error's family across 20 libraries.

Related errors

• --attempts must be an integer from 1 to 20
• --channel, --version and --reason are required
• Choose one Runtime --thread ID.
• Command is required
• Invalid pet recording segment limit.

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/0a75d3c0f04f8243. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/lib.rs:10130

                        );
                    }
                }
            }
            Ok(())
        }
        McpCommand::Add {
            name,
            command,
            url,
            transport,
            bearer_token_env_var,
            oauth_client_id,
            oauth_resource,
            scopes,
            args,
        } => {
            if command.is_none() && url.is_none() {
                bail!("Provide either --command or --url for `mcp add`.");
            }
            if let Some(transport) = transport.as_deref()
                && !transport.trim().eq_ignore_ascii_case("sse")
            {
                bail!("Unsupported MCP transport '{transport}'. Supported values: sse");
            }
            let added_server = McpServerConfig {
                command,
                args,
                env: std::collections::HashMap::new(),
                cwd: None,
                url,
                transport,
                connect_timeout: None,
                execute_timeout: None,
                read_timeout: None,
                disabled: false,
                enabled: true,

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