Warning: This is very early and very experimental software. It is probably not worth running. Things will break, APIs will change, and there is no guarantee of stability.

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One interface. Many gods. Each request goes to the right one.

Pantheon is a cost-aware LLM router for your terminal. Instead of burning through a single provider's token quota, pan routes each conversation to the cheapest model capable of handling it — Gemini Flash for quick questions, Claude Sonnet when you need the heavy hitter.

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How it works

you → pan → classifier → gemini-flash   (free)
                       → claude-haiku   (cheap)
                       → claude-sonnet  (when it matters)

Simple requests go to free/cheap models. Complex reasoning, nuanced writing, and hard coding problems get escalated. You pay for intelligence only when you need it.

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Install

git clone https://github.com/yourusername/pantheon
cd pantheon
cargo install --path .

Development setup

After cloning, activate the git hooks (runs cargo fmt, cargo test, and cargo audit before each push):

git config core.hooksPath .githooks
cargo install cargo-audit  # if not already installed

First run

pan

On first run, pan walks you through adding your first provider (Gemini Flash recommended — it's free).

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Usage

pan              # start a chat session
pan auth add     # add a new provider
pan auth list    # show configured providers
pan config       # view/edit routing config

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Providers

Provider	Model	Tier	Notes
Google	Gemini 2.0 Flash	Free	Recommended starting point
Groq	Llama 3	Free	Very fast inference
Anthropic	Claude Haiku	Cheap	Best cheap quality
Anthropic	Claude Sonnet	Full	Reserved for complex tasks
OpenAI	GPT-4o-mini	Cheap	Good structured output

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Philosophy

The polytheist doesn't pray to one god for everything. Different problems call for different powers. Pantheon routes your requests accordingly.

System Prompt

Pantheon can be started with a custom system prompt by specifying the path to a file in the .pantheon directory.

 pan -s ~/.pantheon/system_prompt.md

Example:

 cat ~/.pantheon/system_prompt.md

Hello, Pantheon!

You can also set the default system prompt to this custom prompt when starting Pantheon:

 pan --custom-system-prompt ~

Hello, Pantheon!