Posit Assistant: support Anthropic-compatible subscriptions (Z.ai GLM Coding Plan, Moonshot Kimi for Coding)Posit Assistant: support Anthropic-compatible subscriptions (Z.ai GLM Coding Plan, Moonshot Kimi for Coding)

Description

Posit Assistant's experimental Custom Provider currently only supports OpenAI-compatible endpoints. Two widely used AI coding subscriptions — the Z.ai GLM Coding Plan (Zhipu) and Moonshot Kimi for Coding — expose Anthropic-compatible endpoints, so today they cannot be connected to Posit Assistant at all.

Problem

• Both plans provide official Anthropic Messages API-compatible endpoints:
  • Z.ai GLM Coding Plan: https://api.z.ai/api/anthropic (docs: https://docs.z.ai/devpack/tool/claude)
  • Moonshot Kimi for Coding: https://api.moonshot.ai/anthropic (docs: https://platform.kimi.ai/docs/overview)
• They are already officially supported by agentic coding tools such as Claude Code, OpenCode, and Cline, and have large and fast-growing user bases (especially, but not only, in China).
• In Positron, the built-in Anthropic provider entry only points to Anthropic itself, and the Custom Provider only speaks the OpenAI protocol. Users whose primary AI subscription is GLM or Kimi therefore have no way to use their plan inside Positron, which pushes this group toward other IDEs.

Proposed solution

Any one of these would help:

1. Extend the Custom Provider to also support the Anthropic Messages API (custom base URL + API key). This single change would make both plans immediately usable, along with any other Anthropic-compatible provider.
2. Add first-class provider entries for Z.ai GLM Coding Plan and Moonshot Kimi for Coding.
3. Longer term, consider subscription/OAuth-style sign-in for these plans, similar to how GitHub Copilot is handled.

Additional context

I'm happy to test preview builds and report compatibility results. For reference, similar requests exist in other coding tools (e.g. anomalyco/opencode#2431 for the GLM Coding Plan).

Thanks for building a great IDE for data science!

The issue names no files or tests. Start by locating Positron Assistant's experimental Custom Provider and its OpenAI-compatible request path, then compare it with the Anthropic Messages API requirements for the listed endpoints. Done means an agreed provider approach supports the stated Z.ai and Moonshot use cases and has compatibility coverage.