---
description: Enforce single-line-or-multiline formatting for Go parameter and argument lists
globs: "**/*.go"
alwaysApply: false
---

# Go multiline parameter and argument lists

Parameter/argument lists are either **all on one line** or **each on its own line** — never mixed.

## Function/method definitions

```go
// GOOD — fits on one line
func (s *Service) GetFoo(ctx context.Context, id gid.GID) (*Foo, error) {

// GOOD — multiline: one param per line, closing ) on its own line
func (s *Service) CreateFoo(
	ctx context.Context,
	tenantID gid.TenantID,
	req CreateFooRequest,
) (*Foo, error) {

// BAD — mixed
func (s *Service) CreateFoo(ctx context.Context, tenantID gid.TenantID,
	req CreateFooRequest) (*Foo, error) {

// BAD — closing ) stuck on last param line
func (s *Service) CreateFoo(
	ctx context.Context,
	req CreateFooRequest) (*Foo, error) {
```

## Call expressions

```go
// GOOD — one line
id := gid.New(tenantID, "Foo")

// GOOD — multiline: one arg per line, trailing comma, closing ) alone
svc, err := foo.NewService(
	ctx,
	db,
	logger,
)

// BAD — some args on the call line, rest below
svc, err := foo.NewService(ctx, db,
	logger,
)

// BAD — first args on the callee line with multiline composite literal
svc, err := foo.NewService(ctx, db, foo.Config{
	MaxRetry: 3,
})

// BAD — single multiline argument starts on the opening ( line
body, err := json.Marshal(firecrawlRequest{
	Query: query,
	Limit: maxResults,
})

// GOOD — single multiline argument: break after (, trailing comma, ) alone
body, err := json.Marshal(
	firecrawlRequest{
		Query: query,
		Limit: maxResults,
	},
)
```

## Quick checklist when writing or reviewing Go code

1. Does the signature/call fit on one line? → keep it on one line.
2. Doesn't fit? → break after `(`, one item per line, `)` on its own line.
3. Never place some items on the opening line and others below.
4. Even a single argument that spans multiple lines must break after `(`.