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Aider

Saturn integrates with Aider, the AI pair programming tool. The saturn aider command browses _saturn._tcp.local., picks an instance by priority, and launches Aider with OPENAI_BASE_URL / OPENAI_API_KEY already populated — no API keys or configuration needed on the user's side.

What it does on the wire

$ dns-sd -B _saturn._tcp .local                 # browse
$ dns-sd -L "<instance>" _saturn._tcp local.    # resolve
$ curl http://<host>:<port>/v1/models           # enumerate models
# ↓ then exec aider with OPENAI_BASE_URL / OPENAI_API_KEY set

Everything below is the Python wrapper for those steps.

Prerequisites

Install both Saturn and Aider:

pip install saturn-ai aider-chat

Ensure at least one Saturn service is running on your network:

saturn run openrouter

Basic usage

saturn aider

This will:

  1. Discover all Saturn services on the network (8-second timeout)
  2. Select the best service based on priority, cost, and capabilities
  3. Pick the first available model from that service
  4. Launch Aider with OPENAI_BASE_URL and OPENAI_API_KEY set automatically

Interactive selection

Use --select to manually choose a server and model:

saturn aider --select

This displays all discovered services with their deployment type, API type, models, context window, cost, and priority.

Model specification

Skip selection entirely by passing a model name:

saturn aider --saturn-model anthropic/claude-sonnet-4-20250514

Filtering

Filter which services are eligible:

# Require specific capabilities
saturn aider --saturn-needs code,chat

# Require minimum context window size
saturn aider --saturn-min-context 64000

# Disable preference for free services
saturn aider --no-saturn-prefer-free

Passing arguments to Aider

Arguments not recognized by Saturn are forwarded directly to Aider:

saturn aider --select -- --no-auto-commits --dark-mode

CLI flags

Flag Default Description
--select off Interactively select server and model
--saturn-model MODEL — Use a specific model (skips selection)
--saturn-needs CAPS — Required capabilities, comma-separated (e.g., code,chat)
--saturn-min-context N 0 Minimum context window size
--saturn-prefer-free / --no-saturn-prefer-free on Prefer free services when ranking
--saturn-verbose off Show discovery details
--timeout SECONDS 8.0 Discovery timeout in seconds

Under the hood

saturn aider calls discover() to find services, then select_best_service() to pick the best one. It fetches the model list from the selected service's /v1/models endpoint, then launches Aider as a subprocess with:

  • OPENAI_BASE_URL set to the service endpoint
  • OPENAI_API_KEY set to the service's ephemeral key (for cloud/beacon services) or saturn (for local services)
  • --model openai/<selected_model> passed to Aider

For cloud services (beacons), Saturn uses the service's api_base and ephemeral key. For local/network services, it uses the discovered endpoint directly.