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pi (gateway)

Route pi’s LLM calls through the Respan gateway for automatic logging, caching, and model switching. pi loads custom providers from ~/.pi/agent/models.json, so only your RESPAN_API_KEY is needed.

This page covers gateway routing. To also capture turns, tool calls, and compactions from inside pi, see pi (tracing).

Setup

1

Install pi

npm install -g --ignore-scripts @earendil-works/pi-coding-agent
2

Add Respan as a provider

Create or edit ~/.pi/agent/models.json:

{
  "providers": {
    "respan": {
      "baseUrl": "https://api.respan.ai/api",
      "api": "openai-completions",
      "apiKey": "$RESPAN_API_KEY",
      "models": [
        {
          "id": "gpt-4o",
          "name": "GPT-4o",
          "reasoning": false,
          "input": ["text", "image"],
          "cost": { "input": 2.5, "output": 10, "cacheRead": 1.25, "cacheWrite": 0 },
          "contextWindow": 128000,
          "maxTokens": 16384
        },
        {
          "id": "claude-sonnet-4-5-20250929",
          "name": "Claude Sonnet 4.5",
          "reasoning": true,
          "input": ["text", "image"],
          "cost": { "input": 3, "output": 15, "cacheRead": 0.3, "cacheWrite": 3.75 },
          "contextWindow": 200000,
          "maxTokens": 64000
        }
      ]
    }
  }
}

Then export the key in your shell profile:

export RESPAN_API_KEY="YOUR_RESPAN_API_KEY"

No separate provider key needed. The Respan gateway handles provider authentication.

3

Run pi

pi --model respan/gpt-4o

For a one-shot, non-interactive run:

pi -p --model respan/gpt-4o "your prompt"

All LLM calls now route through Respan.

Switch models

Add more entries to the models array and pick any of them with --model respan/<id>. Any of the 1000+ models available through the gateway work, for example:

gpt-4o
claude-sonnet-4-5-20250929
gemini/gemini-3.5-flash

See the full model list.

Use a provider-native API

pi also speaks the Anthropic Messages and OpenAI Responses protocols. Point those at the matching Respan passthrough if you prefer the native format:

{
  "providers": {
    "respan-anthropic": {
      "baseUrl": "https://api.respan.ai/api/anthropic",
      "api": "anthropic-messages",
      "apiKey": "$RESPAN_API_KEY",
      "models": [{ "id": "claude-haiku-4-5-20251001", "name": "Claude Haiku 4.5", "reasoning": true, "input": ["text", "image"], "cost": { "input": 1, "output": 5, "cacheRead": 0.1, "cacheWrite": 1.25 }, "contextWindow": 200000, "maxTokens": 64000 }]
    },
    "respan-responses": {
      "baseUrl": "https://api.respan.ai/api",
      "api": "openai-responses",
      "apiKey": "$RESPAN_API_KEY",
      "models": [{ "id": "gpt-5.5", "name": "GPT-5.5", "reasoning": true, "input": ["text", "image"], "cost": { "input": 2, "output": 8, "cacheRead": 0.2, "cacheWrite": 0 }, "contextWindow": 400000, "maxTokens": 128000 }]
    }
  }
}

The openai-responses route only serves OpenAI models. Use openai-completions for Claude, Gemini, and other providers.