What causes "The client doesn't support embeddings api" in sigoden/aichat?

Use a client/provider that implements the embeddings API (e.g. OpenAI) for embedding workloads

The client doesn't support embeddings api

Error message

The client doesn't support embeddings api

What it means

This is the default trait implementation of Client::embeddings_inner in src/client/common.rs. Clients that do not implement the embeddings API inherit this default, which unconditionally fails. Calling embeddings() on such a client therefore always errors — the provider simply has no embeddings capability wired up.

Solutions

Use a client/provider that implements the embeddings API (e.g. OpenAI) for embedding workloads
Check the client's capability before calling embeddings and route to a supported provider
Contribute/implement embeddings_inner for the provider you need
Restructure the app so embedding generation is decoupled from chat provider choice

Example fix

// before
let embeddings = client.embeddings(data).await?;  // fails on Claude/Bedrock client
// after
let embeddings = openai_client.embeddings(data).await?;

Defensive patterns

Strategy: fallback

Validate before calling

// capability check before calling
if !client.supports_embeddings() { /* route to OpenAI */ }

Type guard

fn supports_embeddings(client: &dyn Client) -> bool {
    // only providers that override embeddings_inner
    matches!(client.as_any().downcast_ref::<OpenAIClient>(), Some(_))
}

Try / catch

match client.embeddings(data).await {
    Err(e) if e.to_string().contains("doesn't support embeddings") => {
        openai_client.embeddings(data).await
    }
    r => r,
}

Prevention

Document which providers implement embeddings_inner
Route embedding workloads to embedding-capable providers
Centralize provider capability checks in one config layer
Add a startup assertion when a workflow requires embeddings

When it happens

Trigger: Calling client.embeddings(data) (embeddings -> embeddings_inner) on any client that hasn't overridden embeddings_inner, e.g. the Bedrock, Claude, or Cohere clients.

Common situations: Generic code that calls embeddings on any Client without checking provider capability, switching a config to a provider that doesn't support embeddings, or copy-pasting embeddings code between providers.

Related errors

AI-assisted analysis of sigoden/aichat@82976d349a (2026-09-09). Data as JSON: /api/errors/bf59d5ed440143b9. Report an issue: GitHub.

Appendix: source

Thrown at src/client/common.rs:140

    async fn chat_completions_inner(
        &self,
        client: &ReqwestClient,
        data: ChatCompletionsData,
    ) -> Result<ChatCompletionsOutput>;

    async fn chat_completions_streaming_inner(
        &self,
        client: &ReqwestClient,
        handler: &mut SseHandler,
        data: ChatCompletionsData,
    ) -> Result<()>;

    async fn embeddings_inner(
        &self,
        _client: &ReqwestClient,
        _data: &EmbeddingsData,
    ) -> Result<EmbeddingsOutput> {
        bail!("The client doesn't support embeddings api")
    }

    async fn rerank_inner(
        &self,
        _client: &ReqwestClient,
        _data: &RerankData,
    ) -> Result<RerankOutput> {
        bail!("The client doesn't support rerank api")
    }

    fn request_builder(
        &self,
        client: &reqwest::Client,
        mut request_data: RequestData,
    ) -> RequestBuilder {
        self.patch_request_data(&mut request_data);
        request_data.into_builder(client)
    }

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