BoundaryML/baml · critical · BamlSysError

BAML library not found. Searched paths

Error message

BAML library not found. Searched paths: {searched_paths:?}

What it means

`BamlSysError::LibraryNotFound` from baml-sys, reported via thiserror. The native BAML dynamic library (`.so`/`.dylib`/`.dll`) could not be located at any of the configured search paths at load time. The message lists every path that was searched so you can see what was tried.

Solutions

1. Build or install the native BAML library and place it in one of the listed search paths
2. Fix the library search path configuration / env (e.g. point loader at the actual .so/.dylib/.dll location)
3. Install the correct platform-specific package variant matching your OS/arch

Example fix

// before
let sys = BamlSys::new(&["/opt/nonexistent/lib"])?; // LibraryNotFound
// after
let sys = BamlSys::new(&["/opt/nonexistent/lib", "/usr/local/lib"])?;
// ensure libbaml.so exists: cp target/release/libbaml.so /usr/local/lib/

let paths = candidate_paths();
let missing: Vec<_> = paths.iter().filter(|p| !p.exists()).collect();
if missing.len() == paths.len() { return Err("BAML native library not installed"); }

fn library_present(path: &std::path::Path) -> bool { path.is_file() }

match load_baml_sys() {
    Err(BamlSysError::LibraryNotFound { searched_paths }) => {
        eprintln!("Build/install the native lib; searched: {searched_paths:?}");
    }
    Ok(sys) => { /* use sys */ }
}

When it happens

Trigger: Initializing/loading the BAML library through baml-sys before the native library has been built or installed, or when search paths point to the wrong directories.

Common situations: Fresh clone without building the native lib; library installed to a nonstandard location not on the search path; wrong package variant for your platform; CI images missing the native artifact.

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

• Failed to load BAML library from
• {0}
• Engine not initialized. Call create_baml_runtime first.
• Expected Collector, got
• Expected string value for tag key

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/9aa4a670a0b3a2f1. Report an issue: GitHub.

Appendix: source

Thrown at languages/rust/baml-sys/src/error.rs:10

//! Error types for baml-sys library loading.

use std::path::PathBuf;

/// Errors that can occur during library loading.
#[derive(Debug, thiserror::Error)]
#[allow(missing_docs)] // Error variants are self-documenting via #[error(...)]
pub enum BamlSysError {
    /// Library file not found at any search path.
    #[error("BAML library not found. Searched paths: {searched_paths:?}")]
    LibraryNotFound { searched_paths: Vec<PathBuf> },

    /// Failed to load the dynamic library.
    #[error("Failed to load BAML library from {path}: {source}")]
    LoadFailed {
        path: PathBuf,
        #[source]
        source: libloading::Error,
    },

    /// Symbol not found in loaded library.
    #[error("Symbol '{symbol}' not found in BAML library: {source}")]
    SymbolNotFound {
        symbol: &'static str,
        #[source]
        source: libloading::Error,
    },

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