What causes "no `.baml` files found in {}" in BoundaryML/baml?

Run from the directory containing `baml_src/` with `.baml` files, or pass the correct project path

no `.baml` files found in {}

Error message

no `.baml` files found in {}

What it means

Raised during project loading when the project root (or --from directory) contains no *.baml source files. ProjectSession::open succeeded in finding a directory, but the glob for BAML sources came back empty — the sources may be in a subdirectory not searched, a wrong --from path was given, or the files use a different extension.

Source

Thrown at baml_language/crates/baml_cli/src/run_command.rs:842

    }

    /// Load the project (or standalone `--file`), check diagnostics,
    /// compile to bytecode, create engine.
    fn load_and_compile(&self, argv: Vec<String>, reporter: &Reporter) -> Result<Compiled> {
        if let Some(file) = self.file.as_deref() {
            return self.load_and_compile_standalone(file, argv, reporter);
        }

        let mut session = crate::project_session::ProjectSession::open(
            self.from.as_deref(),
            crate::project_session::CacheUse::ReadWrite,
        )?;
        self.vlog(format_args!(
            "Loading project from {}",
            session.root().display()
        ));
        if session.is_empty() {
            anyhow::bail!("no `.baml` files found in {}", session.root().display());
        }
        self.vlog(format_args!("Found {} .baml file(s)", session.file_count()));
        let needs_format_hint = session.needs_format_hint();

        if let Some(program) = session.try_cached_program() {
            self.vlog(format_args!("Bytecode cache hit — skipping compile"));
            match BexEngine::new_with_runtime_compiler(
                program,
                Arc::new(sys_native::SysOps::native()),
                argv.clone(),
                bex_project::runtime_compiler(),
            ) {
                Ok(engine) => {
                    return Ok(Compiled {
                        db: session.db,
                        package: session.package,
                        engine,
                        needs_format_hint,

View on GitHub (pinned to bd85ce9dee)

Solutions

Run from the directory containing `baml_src/` with `.baml` files, or pass the correct project path
Verify `.baml` files exist under the project root shown in the error
Check the project root configuration in `baml.toml`

Example fix

# before (wrong dir)
cd ./empty_dir && baml run -f MyFn
# after
cd ./my_project && baml run -f MyFn

Defensive patterns

Strategy: validation

Validate before calling

const { globSync } = require('glob'); if (globSync('**/*.baml', { cwd: projectRoot }).length === 0) throw new Error(`no .baml files in ${projectRoot}`);

Prevention

Run baml run from a directory containing .baml sources
Verify project root / baml.toml location before invoking
Keep .baml extension intact when renaming files

When it happens

Trigger: `load_and_compile` finds `session.is_empty()` after loading the project directory — no files matching `*.baml` exist under the resolved project root.

Common situations: Running `baml run` outside a BAML project or in an empty directory; misconfigured project root in `baml.toml`; all `.baml` files moved/deleted or renamed with a wrong extension.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/edc826befc87b1e8. Report an issue: GitHub.