This guide covers PHANTOM_BASE_URL, the address pai sends every Phantom AI call to, and why pai accepts only https:// there.
pai calls https://phantom.codes/v1 ( DEFAULT_BASE_URL). Set PHANTOM_BASE_URL to use another Phantom AI deployment:
export PHANTOM_BASE_URL=https://phantom.example.org/v1
The paths in the interface reference are relative to this address.
pai sends your API key with each call, so it refuses any address that doesn't start with https:// ( httpsOnly). That includes http://localhost: there is no exception for your own machine.
| Problem | Error code |
|---|---|
| the value isn't a web address | base_url_invalid |
the address isn't https:// |
base_url_insecure |
The check runs every time pai builds a Phantom AI address: each API call, fetching the receipt key for verify, and pai setup --agent claude --provider, which writes the address into Claude Code's settings as ANTHROPIC_BASE_URL without the trailing /v1 ( claudeProvider).
A wrong or hostile address still can't make an agent wallet sign more than you asked for: pai checks the payment request it gets back before signing. See Agent wallets and spending caps.
It can serve its own receipt key, since verify fetches the key from the same address. A valid receipt proves the server at PHANTOM_BASE_URL signed it. See Receipts and verify.
These carry no API key, and the https rule doesn't cover them:
PHANTOM_SOLANA_RPC, or Solana's public one for the network,https://api.coinbase.com/v2/prices/SOL-USD/spot, for the SOL price check before a SOL payment,