Backends and Multi-Agent Setup

Vaner is MCP-first: your IDE/agent keeps ownership of chat generation, and Vaner uses a backend to run its ponder loop (scenario ranking, exploration, and precompute).

Default backend (most users)

Vaner Desktop and vaner init default to Ollama on localhost. That is the same default on macOS, Windows, and Linux.

The generated local config looks like this:

[backend]
name = "ollama"
base_url = "http://127.0.0.1:11434/v1"
model = "llama3.2:3b"
api_key_env = ""
prefer_local = true

You can switch to a larger pulled Ollama model later:

vaner config set backend.model qwen3.5:8b --path .

Hosted backends are explicit alternatives:

[backends.openai]
base_url = "https://api.openai.com/v1"
model = "gpt-4o"
api_key_env = "OPENAI_API_KEY"

[backends.claude]
base_url = "https://api.anthropic.com/v1"
model = "claude-sonnet-4-20250514"
api_key_env = "ANTHROPIC_API_KEY"

Use this with MCP mode (vaner mcp --path .): your client calls Vaner tools and Vaner ponders with the configured backend.

Picking local vs hosted

• Local (Ollama, LM Studio, vLLM): best for privacy and predictable cost.
• Hosted (OpenAI, Anthropic, OpenRouter): best when you need stronger reasoning or larger context windows.

Multi-backend profiles

Named profiles are useful if you switch between a cheap/default model and a heavier model for deeper exploration.

Vaner also supports per-client isolation:

• Send X-Vaner-Client to isolate context traces per agent.
• Use vaner inspect --last --client <id> for client-specific visibility.

Advanced: gateway-mode per-request overrides

Only in proxy/gateway mode can a caller select a backend profile per HTTP request via headers:

X-Vaner-Backend: openai

Multi-repo override is disabled by default and should only be enabled intentionally:

[proxy]
allow_repo_override = true

If your client supports MCP directly, skip these gateway controls and stay on MCP mode.