positional `<TARGET>` is a function name, not a file path. F

Error message

positional `<TARGET>` is a function name, not a file path. For a single-file source, use `--file {target}` and pass the function via `-f <NAME>`. For example:

    `baml run --file {target} -f <NAME>`

What it means

The positional `<TARGET>` argument of `baml run` is a function (or script) name, never a file path. When the value looks like a path (e.g. `baml_src/main.baml`), the CLI redirects the user to `--file` for single-file source and `-f <NAME>` for the function.

Source

Thrown at baml_language/crates/baml_cli/src/run_command.rs:485

        if self.file.is_some() && self.target.is_none() && self.functions.is_empty() {
            return self.run_single_target("main", reporter);
        }

        // No target → print help and exit non-zero. (Implicit `main` no
        // longer exists.)
        if self.target.is_none() && self.functions.is_empty() {
            Self::print_run_help();
            return Ok(crate::ExitCode::Other);
        }

        if let Some(target) = &self.target {
            // Helpful redirect when the user typed a path as the
            // positional (e.g. `baml run baml_src/main.baml`). Positional
            // `<TARGET>` is always a function name; for a `.baml` source
            // use `--file`.
            if looks_like_path(target) {
                anyhow::bail!(
                    "positional `<TARGET>` is a function name, not a file path. \
                     For a single-file source, use `--file {target}` and pass the \
                     function via `-f <NAME>`. For example:\n\
                     \n    `baml run --file {target} -f <NAME>`\n",
                );
            }
            return self.run_single_target(target, reporter);
        }
        self.run_subcommand_targets(reporter)
    }

    /// Positional `<TARGET>` path: one function, no subcommand layer.
    /// `[scripts]` aliases are resolved here too (positional only).
    fn run_single_target(&self, target: &str, reporter: &Reporter) -> Result<crate::ExitCode> {
        let argv = self.build_argv_for_single(target);
        let Compiled {
            db,
            package,

View on GitHub (pinned to bd85ce9dee)

Solutions

Pass the file via `--file` and the function name via `-f <NAME>`
Use `baml run --file <path> -f <functionName>` instead of a positional path
If you meant a function, pass just the function name as the positional

Example fix

// before
baml run baml_src/main.baml
// after
baml run --file baml_src/main.baml -f MyFunction

Defensive patterns

Strategy: validation

Validate before calling

if (positional && /\.[^.\/\\]+$|\//.test(positional)) { throw new Error(`Use --file ${positional} -f <NAME> instead of a positional path`); }

Prevention

Remember positional <TARGET> is a function/script name, not a path
Use --file for any .baml source path
Keep function names free of path-like characters (/, .ext)

When it happens

Trigger: Running e.g. `baml run baml_src/main.baml` — passing a `.baml` file path as the positional target so `looks_like_path(target)` is true.

Common situations: Developers accustomed to other CLIs where a file path is the primary argument type a path-style target.

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

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/98c2bb099c54350d. Report an issue: GitHub.