zed-industries/zed · error · LanguageModelCompletionError

{display_name} is not available in {region} because Bedrock

Error message

{display_name} is not available in {region} because Bedrock Mantle isn't offered there. Try switching to one of the following regions: {supported}.

What it means

Refusal at stream_completion: the configured AWS region is not in MANTLE_SUPPORTED_REGIONS, so the Bedrock Mantle model cannot be invoked there. Fires before any network call, as a regional-availability guard for models whose endpoint only exists in specific AWS regions.

Source

Thrown at crates/language_models/src/provider/bedrock.rs:1880

            LanguageModelToolChoice::Auto | LanguageModelToolChoice::Any => {
                self.model.supports_tools()
            }
            LanguageModelToolChoice::None => true,
        }
    }

    fn supports_streaming_tools(&self) -> bool {
        true
    }

    fn supports_thinking(&self) -> bool {
        self.model.supports_thinking()
    }

    fn supported_effort_levels(&self) -> Vec<LanguageModelEffortLevel> {
        mantle_supported_effort_levels(&self.model)
    }

    fn supports_split_token_display(&self) -> bool {
        true
    }

    fn telemetry_id(&self) -> String {
        format!("bedrock-mantle/{}", self.model.id())
    }

    fn max_token_count(&self) -> u64 {
        self.model.max_token_count()
    }

    fn max_output_tokens(&self) -> Option<u64> {
        Some(self.model.max_output_tokens())
    }

    fn stream_completion(
        &self,

View on GitHub (pinned to 5a9b9558db)

Solutions

1. Switch the AWS region in settings to one listed in the error's supported regions
2. Choose a non-Mantle Bedrock model that is offered in the current region

When it happens

Trigger: Thrown at crates/language_models/src/provider/bedrock.rs:1889 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@5a9b9558db (2026-08-20). Data as JSON: /api/errors/09877e1498710202. Report an issue: GitHub.