Add provider-specific usage details, fix streaming usage, and return
usage from all high-level APIs (Chat.Send, Generate[T], Agent.Run).
Breaking changes:
- Chat.Send/SendMessage/SendWithImages now return (string, *Usage, error)
- Generate[T]/GenerateWith[T] now return (T, *Usage, error)
- Agent.Run/RunMessages now return (string, *Usage, error)
New features:
- Usage.Details map for provider-specific token breakdowns
(reasoning, cached, audio, thoughts tokens)
- OpenAI streaming now captures usage via StreamOptions.IncludeUsage
- Google streaming now captures UsageMetadata from final chunk
- UsageTracker.Details() for accumulated detail totals
- ModelPricing and PricingRegistry for cost computation
Closes#2
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
v2 is a new Go module (v2/) with a dramatically simpler API:
- Unified Message type (no more Input marker interface)
- Define[T] for ergonomic tool creation with standard context.Context
- Chat session with automatic tool-call loop (agent loop)
- Streaming via pull-based StreamReader
- MCP one-call connect (MCPStdioServer, MCPHTTPServer, MCPSSEServer)
- Middleware support (logging, retry, timeout, usage tracking)
- Decoupled JSON Schema (map[string]any, no provider coupling)
- Sample tools: WebSearch, Browser, Exec, ReadFile, WriteFile, HTTP
- Providers: OpenAI, Anthropic, Google (all with streaming)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
