Authentication

See also docs/concepts/auth/oauth.md for the design of pi-go’s OAuth transport. CLI credentials are stored at ~/.pigo/auth.json per CLAUDE.md.

API Key

Provider	API	pi-go	Notes
Anthropic	✅	✅	WithAPIKey (anthropic.go:372-374)
OpenAI Chat	✅	✅	passed via option.RequestOption
OpenAI Responses	✅	✅
Google Gemini	✅	✅	WithAPIKey (google.go:39-41)
Claude CLI	✅ via ANTHROPIC_API_KEY env	✅	inherits process env
Codex CLI	✅ via Codex CLI auth	✅	delegated to the codex subprocess

OAuth

Provider	API	pi-go	Notes
Anthropic	✅ Claude.ai OAuth	✅	authorize endpoint https://claude.com/cai/oauth/authorize, token endpoint https://platform.claude.com/v1/oauth/token, beta header claude-code-20250219,oauth-2025-04-20 (oauth.go:111)
OpenAI Chat	✅ ChatGPT OAuth	✅	NewWithOAuth (oauth.go:114-119); endpoint https://auth.openai.com/oauth/token
OpenAI Responses	⚠️ via the same OAuth as Chat	❌	not implemented in this provider
Google Gemini	✅ Vertex OAuth (gcloud)	❌	pkg/ai/provider/google is API-key only
Claude CLI	✅ delegated to CLI’s own login	✅
Codex CLI	✅ delegated to CLI’s own login	✅

Service Account / Cloud Endpoints

Variant	API	pi-go	Notes
Anthropic on Bedrock	✅	❌	not implemented
Anthropic on Vertex	✅	❌	not implemented
OpenAI on Azure	✅ Azure OpenAI	❌	not implemented
Google on Vertex AI	✅ ADC / service account	❌	pkg/ai/provider/google uses generativelanguage.googleapis.com only

Provider Documentation

• Anthropic — API keys
• Anthropic — OAuth applications
• Anthropic on Bedrock
• Anthropic on Vertex
• OpenAI — Authentication
• Azure OpenAI
• Google Gemini — API keys
• Google — gcloud OAuth
• Google Vertex AI auth

pi-go Gaps

• OpenAI Responses provider has no NewWithOAuth helper; would need to mirror the wiring from openai.
• Google HTTP provider has no OAuth or service-account helper.
• No Bedrock / Vertex routing for Anthropic models.
• No Azure OpenAI variant.
• Login UX (browser redirect, code capture) lives in cmd/pi; not exposed as a reusable library entry point.