BAML internal error (google-ai): file should have been resol

Error message

BAML internal error (google-ai): file should have been resolved to base64

What it means

Google AI media messages must have their content resolved to base64 or URL before to_media_message builds inline_data/file_data payloads. A surviving BamlMediaContent::File means the resolution pass did not inline the file, so BAML treats it as a broken internal invariant and bails.

Source

Thrown at engine/baml-runtime/src/internal/llm_client/primitive/google/googleai_client.rs:385

                content.insert(
                    "inline_data".into(),
                    json!({
                        "mime_type": media.mime_type_as_ok()?,
                        "data": data.base64
                    }),
                );
                Ok(content)
            }
            BamlMediaContent::Url(data) => {
                // Pass through external media via `file_data` as required by Gemini API.
                let mut file_data = json!({ "file_uri": data.url });
                if let Some(mime) = &media.mime_type {
                    file_data["mime_type"] = json!(mime);
                }
                content.insert("file_data".into(), file_data);
                Ok(content)
            }
            BamlMediaContent::File(_) => anyhow::bail!(
                "BAML internal error (google-ai): file should have been resolved to base64"
            ),
        }
    }

    fn role_to_message(
        &self,
        content: &RenderedChatMessage,
    ) -> Result<serde_json::Map<String, serde_json::Value>> {
        let mut message = serde_json::Map::new();
        message.insert("role".into(), json!(content.role));
        message.insert(
            "parts".into(),
            json!(self.parts_to_message(&content.parts)?),
        );
        Ok(message)
    }
}

View on GitHub (pinned to bd85ce9dee)

Solutions

Upgrade BAML to the latest version.
Pass the media as a public URL or inline base64 data instead of a raw file reference.
Verify the referenced file exists and is readable so resolution can succeed.
Report a repro to baml-lang/baml if a valid file reference still fails.

Example fix

// before
img baml_image({ url: "file://./photo.jpg" }) // unresolved
// after
img baml_image({ url: "data:image/jpeg;base64,<base64-data>" })

Defensive patterns

Strategy: validation

Validate before calling

if (media.url?.startsWith('file://')) { media.url = 'data:' + mime + ';base64,' + fs.readFileSync(media.url.slice(7)).toString('base64'); }

Type guard

const isResolvedMedia = (m) => typeof m.url === 'string' && (m.url.startsWith('data:') || m.url.startsWith('http'));

Try / catch

try { await b.GoogleAiPrompt(media) } catch (e) { if (String(e).includes('google-ai): file should have been resolved')) { /* inline base64 / upgrade BAML */ } else throw e; }

Prevention

Send URLs or base64 data to google-ai clients, not raw file refs.
Ensure referenced files exist and are readable.
Keep the BAML runtime version current.

When it happens

Trigger: Sending image/video/pdf media with an unresolved File content reference to a google-ai client — i.e. the file-to-base64 resolution step failed or was bypassed before message construction.

Common situations: Referencing a local media file that BAML failed to resolve (bad path, build/version bug) in a google-ai backed prompt, or programmatically constructed media that skips resolution.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/711b560faa17f002. Report an issue: GitHub.