Fantasy Development Guide

Commands

• Build: go build ./...
• Test all: task test or go test ./... -count=1 -timeout=30m
• Test single: go test -run TestName ./package -v
• Lint: task lint or golangci-lint run
• Lint fix: task lint:fix
• Format: task fmt (uses gofumpt, not gofmt)

Style Notes

• Prefer cmp.Or for defaults
• Struct tags json, description, enum drive schema generation
• charm.land/x/vcr for HTTP test recording (not go-vcr)

Project Layout

• / — Core package fantasy: Provider, LanguageModel, Agent, Content, Tool, errors, retry
• /providers/{openai,anthropic,google,bedrock,azure,openrouter,openaicompat,vercel,kronk}
• /object — Typed structured outputs: object.Generate[T], object.Stream[T]
• /schema, /jsonrepair — JSON schema generation and repair utilities
• /providertests — Integration tests with VCR cassettes in testdata/

Testing

• Env vars: FANTASY_<PROVIDER>_API_KEY, loaded from .env via godotenv
• VCR recorder injected as http.Client transport