Dagger Codegen

When to Load This Skill

• Editing dagger.gen.go or internal/dagger/dagger.gen.go output
• Modifying Go templates in cmd/codegen/generator/go/templates/
• Changing SDK interfaces in core/sdk.go
• Working on dagger develop, dagger call, or dagger client install
• Debugging why generated code looks wrong

Critical Concepts

"Codegen" means 4 different things in Dagger:

#	Name	Trigger	Key Files
1	In-Module Bindings	dagger develop	cmd/codegen/generator/go/templates/
2	Runtime Dispatch	Module startup	cmd/codegen/generator/go/templates/modules.go:140
3	SDK Libraries	go generate	sdk/go/generate.go
4	Generated Clients	dagger client install	_dagger.gen.go/client.go.tmpl

Know which one you're dealing with before editing.

Key Entry Points

To change...	Edit
Generated method signatures	cmd/codegen/generator/go/templates/src/_types/object.go.tmpl
Generated type definitions	cmd/codegen/generator/go/templates/src/_types/*.go.tmpl
Module invoke() dispatch	cmd/codegen/generator/go/templates/modules.go:140
Standalone client Connect()	cmd/codegen/generator/go/templates/src/_dagger.gen.go/client.go.tmpl
Template functions	cmd/codegen/generator/go/templates/functions.go:54
SDK interfaces	core/sdk.go:20 (ClientGenerator), :93 (CodeGenerator)
Built-in SDK list	core/sdk/consts.go
Python output	sdk/python/codegen/src/codegen/generator.py

Reference Files

Load based on specific need:

Need	Load
Understanding the 4 codegen types	codegen-types.md
SDK architecture, interfaces, Go special case	sdk-architecture.md
Go template conditionals, two-pass generation	go-templates.md
dagger client install internals	generated-clients.md