[FEAT]: Add custom base URL for Anthropic provider and optional model discovery for Generic OpenAI

[raucodes]

What would you like to see?

What would you like to see?

I would like to request two related improvements for self-hosted / compatible API backends:

1. Add custom base URL / custom host support to the Anthropic provider
2. Add optional model discovery / model selection support to the Generic OpenAI provider

Why is this needed?

There are now local/self-hosted backends that expose APIs compatible with OpenAI and/or Anthropic.

For example, some backends support:

• OpenAI-compatible /v1/chat/completions
• OpenAI-compatible /v1/models
• Anthropic-compatible /v1/messages
• streaming
• reasoning / thinking
• tool calling

A good example is oMLX, which advertises itself as a drop-in replacement for both OpenAI and Anthropic APIs.

Problem today

1. Anthropic provider

The Anthropic connector appears to be tied to Anthropic-hosted endpoints only, with no way to set a custom host / base URL.

That makes it impossible to use Anthropic-compatible self-hosted backends directly.

2. Generic OpenAI provider

The Generic OpenAI connector works with custom hosts, but it appears to require a manually entered model name and does not seem to expose the same model selection UX as more specific providers.

This means that even when a backend supports GET /v1/models, users cannot conveniently pick from available models in the UI.

Expected behavior

Anthropic provider

Please allow:

• API Key
• Model
• Base URL / Custom Host

Example:

• https://api.anthropic.com
• http://localhost:8080
• https://my-self-hosted-backend.example.com

Generic OpenAI provider

Please optionally support:

• calling GET /v1/models
• populating the model dropdown from that endpoint
• falling back to manual model entry when model discovery is unavailable

Why this would help

This would make AnythingLLM much more flexible for:

• self-hosted backends
• OpenAI-compatible servers
• Anthropic-compatible servers
• private/local inference infrastructure
• advanced users who do not want to rely only on hosted APIs

It would also reduce friction when testing backends that already expose standards-compatible endpoints.

Additional context

Right now, Generic OpenAI is often the best workaround for self-hosted backends because it supports custom hosts, but it may miss provider-specific UX features such as model selection.

At the same time, the Anthropic provider could be a better fit for Anthropic-compatible servers, but only if custom base URLs are supported.

[svar2388]

I just ran into this issue as well. I hooked up NanoGPT to the generic OpenAI connector but was surprised that it would not enumerate the models from the /v1/models endpoint, instead having to manually select only a single model.

[1nhale]

I also ran into this same issue. Hosted an azure anthropic on foundry but cant change the baseurl and also API key is binded to anthropic hosted models only.