Providers

PiG speaks to inference providers through the provider registry shared with its Pi compatibility model. Each built-in provider has a Go implementation under ai/ that handles authentication, request shaping, and stream parsing. Extensions can register additional providers through the public extension API. See Extensions.

Built-in providers

Authentication

PiG stores credentials in ~/.pig/agent/auth.json. The file is created on demand by pig login and is never read at module init. Environment variables (OPENAI_API_KEY, etc.) always take precedence over stored credentials at request time, matching upstream behavior - this lets per-shell or per-project keys override the global file.

OAuth providers

Built-in OAuth targets include anthropic, github-copilot, kimi-coding, openai-codex, openrouter, and xai. Each provider owns its flow. For example, GitHub Copilot uses device authorization, while callback-based providers can open a localhost callback server. Tokens are persisted to auth.json unless the provider owns another store, and supported providers refresh them when required.

A failed Copilot refresh reports an explicit reauthentication instruction:

github-copilot: refresh failed - run 'pig login' to re-authenticate

pig login shapes

pig login                 # interactive picker
pig login <provider>      # specific provider
pig logout <provider>     # remove credentials for one provider

Credential commands

pig auth resolves credentials the way a model request does and writes them for external clients. Each command needs --provider <provider>, --model <model>, or both.

pig auth check --provider openai --json      # ready / not_ready / invalid, exit 0 / 1 / 2
pig auth print-api-key --provider openai     # API key on stdout
pig auth print-bearer-token --provider openai-codex --min-expiry 1h

Credential-printing commands write secrets to stdout. auth check prints a credential only with --credentials.

An OAuth login can wait for device authorization or a browser callback. This wait belongs to the provider flow. PiG does not start a model Session while pig login runs.

Environment variables (auth)

Provider resolution

When you select a model through --model, /model, Ctrl+P, or setModel(), PiG parses provider/model. Always use provider-qualified model specs from extensions and helpers; bare IDs default to openai and can route incorrectly.

For Copilot models the model ID itself may contain a slash (e.g. github-copilot/openai/gpt-5.5); pig's generatedModelSpec helper preserves trailing slashes when rebuilding specs from generated model objects.

Provider extensions

Extensions can add inference providers at register time. The host treats the config payload as opaque. The host owns lifecycle: providers registered by an extension are unregistered automatically on shutdown, reload failure, or quarantine fission. When a reload replaces an extension whose new register declares the same provider name, the registration is preserved across the swap so streaming completions are not interrupted.

Troubleshooting