BoundaryML/baml · error · RenderError

Enum '{0}' not found

Error message

Enum '{0}' not found

What it means

RenderError::EnumNotFound is raised by the sys_ops output_format renderer when asked to render a value whose enum name does not exist in the type registry available to the renderer. The '{0}' placeholder is the enum name string. It is a lookup failure, not a value problem: the type itself is missing from the loaded schema.

Source

Thrown at baml_language/crates/sys_ops/src/output_format.rs:11

use std::fmt::Write as _;

use ::sys_types::SapTy;
use baml_base::Literal as LiteralValue;
use indexmap::IndexMap;
use thiserror::Error;

/// Error type for output format rendering.
#[derive(Clone, Debug, Error)]
pub enum RenderError {
    #[error("Enum '{0}' not found")]
    EnumNotFound(String),
    #[error("Class '{0}' not found")]
    ClassNotFound(String),
    #[error("Type '{0}' is not supported in outputs")]
    UnsupportedType(String),
    #[error(
        "Non-regular recursive generic class '{class}' expands from '{ancestor}' to '{instantiation}'"
    )]
    NonRegularRecursiveGeneric {
        class: String,
        ancestor: String,
        instantiation: String,
    },
    #[error(
        "Output definitions '{first}' and '{second}' both render as '{rendered_name}' in the output schema"
    )]
    RenderedClassNameCollision {
        rendered_name: String,

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Load all BAML source files defining the referenced enum into the renderer's registry
2. Regenerate client code after renaming/removing enums
3. Fix the enum name typo in the code or template referencing it
4. Check renderer setup so the correct project's type registry is attached

Example fix

// before
render(value, registry_without_enums)  // EnumNotFound('Color')
// after
const registry = load_registry(src_files_including_enums_baml);
render(value, registry)

function enumIsRenderable(registry, name) {
  return registry.enums.some(en => en.name === name);
}
// call before render: enumIsRenderable(registry, valueTypeName)

function isEnumNotFoundError(e) {
  return e instanceof Error && /Enum '.*' not found/.test(e.message);
}

try {
  rendered = render(value, registry);
} catch (e) {
  if (isEnumNotFoundError(e)) {
    rendered = String(value); // fallback rendering
  } else throw e;
}

When it happens

Trigger: Rendering output for a response referencing an enum that is not defined in the loaded BAML sources, or after renaming an enum without regenerating/reloading the client.

Common situations: Partial file sets given to the renderer, stale generated code after schema edits, or typos in enum names in templates/config that reference output types.

Related errors

• Class '{0}' not found
• Type '{0}' is not supported in outputs
• Enum {name} not found
• Enum {} does not exist
• Enum {} does not exist

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/ba90462230ea5989. Report an issue: GitHub.