# Use Xantly with GitHub Copilot CLI

**Skip the $10/mo Copilot subscription. Keep the agent. Own your tokens.**

On April 7, 2026, GitHub shipped BYOK support for the Copilot CLI, four environment variables and no GitHub auth required. Point them at Xantly and you get Copilot's coding agent with Xantly's routing, semantic cache, and memory underneath. Your tokens, your margins, no subscription on top.

This is the cleanest "escape hatch" integration in the ecosystem right now. 2-minute setup.

## Prerequisites

- GitHub Copilot CLI installed: `gh extension install github/gh-copilot` (requires the `gh` CLI)
- A Xantly API key, [create one](/dashboard/api-keys) if you don't have one yet

## Setup

Export four environment variables and the Copilot CLI will route every request through Xantly instead of GitHub's proxy:

```bash
export COPILOT_PROVIDER_BASE_URL="https://api.xantly.com/v1"
export COPILOT_PROVIDER_API_KEY="xantly_sk_..."   # your Xantly key
export COPILOT_MODEL="xantly/auto-quality"         # or a specific model
export COPILOT_PROVIDER_TYPE="openai"              # Xantly speaks OpenAI-compatible
```

Drop those in your `~/.zshrc` or `~/.bashrc` to make them persistent.

## Model choice

`COPILOT_MODEL` accepts any model ID from Xantly's catalog. Recommended:

| Setting | Behavior |
|---|---|
| `xantly/auto-quality` | BaRP routes from the T1 pool (Claude Sonnet, GPT-5.x, etc.). Best for complex refactors. |
| `xantly/auto-value` | T2 pool, balanced cost/quality. Best default for daily use. |
| `xantly/auto-speed` | T3 pool, fastest, cheapest. Best for `git commit` messages, quick edits. |
| `anthropic/claude-sonnet-4.6` | Pin to a specific Anthropic model. Xantly honors it exactly, no re-routing. |
| `openai/gpt-5.4` | Pin to OpenAI. Xantly passes through. |

Run `curl https://api.xantly.com/v1/models -H "Authorization: Bearer $COPILOT_PROVIDER_API_KEY"` to see the full live catalog.

## Verify

```bash
gh copilot suggest "a command that finds all files larger than 1MB"
```

The CLI will call Xantly, which routes to a cost-optimal model, returns the answer, and logs the request in your Xantly dashboard. Open the dashboard, you'll see the request, the model it landed on, the cache status, and the cost in USD.

## What you get that stock Copilot CLI doesn't

- **Semantic cache.** Repeated prompts (you often re-run `gh copilot suggest` with slight variations) hit L1/L2 cache and return instantly at near-zero cost.
- **Waterfall fallback.** If OpenAI 500s, Xantly silently falls back to Anthropic or Groq. Copilot CLI just keeps working.
- **Per-request cost visibility.** Every call is tracked. See which commands cost you what.
- **Memory.** Ask Copilot the same question in two weeks, Xantly's memory layer can surface the prior answer if you opt in via `X-Xantly-Memory-Mode: recall`.
- **Budget caps.** Set a monthly USD budget per API key. When you hit it, Xantly returns 402 instead of running up a bill.

## Cost comparison

A developer running ~200 Copilot CLI requests/day on Copilot Pro at $10/mo pays flat regardless of usage. The same pattern through Xantly at smart routing:

- 70% of requests hit `xantly/auto-speed` (cents/day)
- 25% hit `xantly/auto-value`
- 5% hit `xantly/auto-quality`
- **Typical monthly cost: $3-6**, plus semantic-cache savings on repeats.

You break even vs Copilot Pro around 30-50 requests/day. Power users routinely save 40-60%.

## Troubleshooting

**`COPILOT_PROVIDER_BASE_URL` is ignored.** Make sure you're on `gh copilot` version 1.4.0+ (released April 7, 2026). Run `gh copilot --version` to check.

**Rate-limit errors from Xantly.** Set `COPILOT_MODEL=xantly/auto-speed` to get into the high-throughput T3 pool, or upgrade your Xantly plan.

**Model not found.** Make sure the model ID is in `GET /v1/models`. The CLI doesn't pre-validate; Xantly returns 400 with the list of valid IDs if you typo a slug.

## Next steps

- [Cline in VS Code](/docs/use-with-cline), same "BYOK every agent call" pattern but with full IDE integration.
- [Bring Your Own Key](/docs/bring-your-own-key), if you already have provider credits and want Xantly to use them instead of its catalog credentials.
- [Intelligence Modes](/docs/intelligence-modes), fine-tune the pipeline (memory on/off, cache aggressiveness) per request via `X-Xantly-Intelligence-Mode` header.