BoundaryML/baml · error · RuntimeError

error while invoking baml-cli

Error message

error while invoking baml-cli

What it means

Raised by the Ruby FFI's invoke_runtime_cli when the embedded baml-cli runtime returns an error. The original anyhow error context is formatted with {:?} into a Ruby RuntimeError. It means a baml-cli invocation (e.g. generate) run from inside the Ruby extension failed, with the CLI's own error chain embedded in the message.

Source

Thrown at engine/language_client_ruby/ext/ruby_ffi/src/lib.rs:312

        ruby_to_json::RubyToJson::serialize_baml(ruby, types, partial_types, allow_partials, parsed)
            .map_err(|e| {
                magnus::Error::new(
                    ruby.exception_type_error(),
                    format!("failed coercing BAML value to Ruby value: {e:?}"),
                )
            })
    }
}

fn invoke_runtime_cli(ruby: &Ruby, argv0: String, argv: Vec<String>) -> Result<u32> {
    match baml_cli::run_cli(
        std::iter::once(argv0).chain(argv).collect(),
        baml_runtime::RuntimeCliDefaults {
            output_type: baml_types::GeneratorOutputType::RubySorbet,
        },
    ) {
        Ok(exit_code) => Ok(exit_code.into()),
        Err(e) => Err(Error::new(
            ruby.exception_runtime_error(),
            format!(
                "{:?}",
                e.context("error while invoking baml-cli".to_string())
            ),
        )),
    }
}

#[magnus::init(name = "ruby_ffi")]
fn init(ruby: &Ruby) -> Result<()> {
    baml_log::init().map_err(|e| {
        Error::new(
            ruby.exception_runtime_error(),
            format!("Failed to initialize BAML logger: {e:#}"),
        )
    })?;

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Read the {:?}-formatted error chain after 'error while invoking baml-cli' — it names the underlying CLI failure (file, line, reason).
2. Run `baml-cli generate` manually in the same directory to see the full interactive error output.
3. Fix syntax/schema errors in the .baml files reported by the CLI.
4. Verify the baml_src directory exists and is reachable from the process working directory (use Dir.pwd / absolute paths).
5. Check that CLI arguments passed to the FFI call are valid (no stray flags or bad paths).

Example fix

// before
result = Baml::Ffi.invoke_runtime_cli("generate", argv)

// after
begin
  result = Baml::Ffi.invoke_runtime_cli("generate", argv)
rescue RuntimeError => e
  warn "baml-cli failed: #{e.message}"
  raise unless e.message.include?("no baml files")
end

raise 'baml_src not found' unless Dir.exist?('baml_src')
system('baml-cli', 'generate', out: File::NULL) or raise 'baml-cli not runnable in this env'

begin
  code = Baml::Ffi.invoke_runtime_cli('generate', argv)
rescue RuntimeError => e
  warn "baml-cli failed: #{e.message}"
  raise unless e.message.include?('No such file')
end

When it happens

Trigger: Invoking baml-cli through the Ruby FFI (invoke_runtime_cli) when the runtime command fails: missing/invalid baml_source directory, syntax errors in .baml files, unreadable working directory, or invalid CLI arguments passed through argv.

Common situations: Running `Baml::Ffi.compile` or codegen from a Rails initializer where the baml_src path is wrong; .baml files with schema errors; running the CLI with defaults that expect Ruby Sorbet output in a project not set up for it.

Understand the failure class

Background: "Unknown argument", "Invalid value", and "must be one of": invalid CLI argument errors explained — this error's family across 35 libraries.

Related errors

• compilation failed: {e:?}
• failed to generate Go SDK: {error}
• compilation failed: {e:?}
• no `.baml` files found in {}
• could not find packaged playground assets. For local debuggi

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/01ea9fa74c3922dd. Report an issue: GitHub.