Claude Desktop

Connect Claude Desktop to Mixen — pay from your balance in roubles, with the Anthropic Messages protocol: tool calling, streaming, and prompt caching.

Claude Desktop is Anthropic’s application with three tabs: Chat, Cowork, and Code. A custom API endpoint is configured not through environment variables (the app reads neither ANTHROPIC_BASE_URL nor settings.json — unlike the CLI, see Claude Code) but through its built-in third-party inference configuration. Mixen implements the Anthropic Messages protocol, so it plugs in as such a provider; development sessions (the Code tab) are what gets routed through the gateway.

Setup

1. Open Help → Troubleshooting → Enable Developer Mode — the app restarts with a Developer menu.
2. Open Developer → Configure Third-Party Inference…
3. In the Connection section, set Inference provider to Gateway.
4. Fill in the Gateway credentials card:

Field	Value
Gateway base URL	https://api.mixen.ai
Gateway API key	your mxn-… key from the dashboard
Credential kind	Static API key
Gateway auth scheme	Bearer (default) or x-api-key — Mixen accepts both

Key points:

• The base URL carries no /v1 suffix: the app appends /v1/messages to the request path itself.
• The gateway requirements are POST /v1/messages with streaming and tool use; Mixen supports all of it (the same surface Claude Code uses).
• GET /v1/models for model auto-discovery is optional. If the model picker is empty or missing what you need — set the models explicitly, by full IDs from the catalog: anthropic/claude-sonnet-5 and so on. Bare aliases like sonnet do not resolve without discovery.

Limitations

With a gateway active, the app runs sessions locally only: the environment picker offers no SSH hosts or Anthropic-hosted cloud environments, and Remote Control is unavailable. If you need the agent on a remote machine — run the CLI there with the variables from the Claude Code guide.

What is supported

The gateway exposes the same Mixen surface Claude Code uses (the Anthropic Messages protocol):

Feature	Status
Text, system, images (vision models)	✅
Tools / tool use	✅
Streaming SSE (stream: true)	✅
POST /v1/messages/count_tokens	✅ (an estimate without calling the model)
Prompt caching (cache_control)	✅
Extended thinking (thinking)	✅

Verifying the connection

The key and balance are checked with a minimal generating request:

curl https://api.mixen.ai/v1/chat/completions \
  -H "Authorization: Bearer your-api-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"z-ai/glm-5.3-flash","messages":[{"role":"user","content":"ping"}],"max_tokens":5}'

200 — the key and balance work; 401 — the key was copied incompletely or it is not a Mixen API key; 402 — the balance is empty. If the app shows Gateway was unreachable at startup, it could not reach the base URL — check the address (no /v1) and the network.

Recommended models

Every text model in the catalog is available over the Anthropic Messages protocol; IDs pass through as is. Prices are per 1M tokens, input/output; full tables with cache columns — in the catalog.

Task	Model	Input / output
Quick questions, routine, drafts	GLM 5.3 Flash (z-ai/glm-5.3-flash)	8.4 / 27.9 ₽
Edits in familiar code, long tasks	GLM 5.3 (z-ai/glm-5.3)	156 / 490.2 ₽
Complex agentic sessions, unfamiliar codebase	Claude Sonnet 5 (anthropic/claude-sonnet-5)	213.9 / 1069.5 ₽

Cache and session savings

Prompt caching is always on at Mixen; the client needs no setup:

• repeated context within 5 minutes is billed at ~10% of the input price (21.4 ₽ per 1M for claude-sonnet-5 instead of 213.9 ₽, 1.7 ₽ for glm-5.3-flash), and every hit extends the window by another 5 minutes;
• a pause longer than 5 minutes resets the cache — the next turn pays the full input price, then the discount builds up again;
• don’t edit project rules (CLAUDE.md, AGENTS.md) mid-session — changing the prefix resets the cache;
• the limit is 60 RPM per key.

Troubleshooting

• Gateway was unreachable — the app could not reach the base URL at startup: make sure the address has no /v1 and your network doesn’t block api.mixen.ai.
• ANTHROPIC_BASE_URL / settings.json variables don’t work — that’s expected: Desktop only reads third-party inference configuration from the Developer form. For environment variables use the CLI (see the Claude Code page).
• The model picker is empty — auto-discovery only shows recognizably-Claude models; set an explicit list with full catalog IDs.
• The configuration form is read-only — an administrator-distributed configuration (MDM) is already on the device; it takes precedence over the local one.