---
action: context
tool: (edit|write)
event: after
name: use-console-service
description: Use Effect Console or Effect.log instead of console
glob: '**/*.{ts,tsx}'
detector: ast
pattern: console.$M($$$)
level: warning
suggestSkills:
    - effect-observability
---

# Use Effect Console Instead of console.\*

```haskell
-- Transformation
console.log   :: String → IO ()      -- side effect, not composable
console.error :: String → IO ()      -- same problem

-- Instead
Console.log   :: String → Effect () Console
Effect.log    :: String → Effect () ∅        -- with structured logging
Effect.logError :: String → Effect () ∅
```

```haskell
-- Pattern
bad :: Effect ()
bad = do
  Effect.sync \_ → console.error "Error:" error   -- ceremony with no benefit

good :: Effect ()
good = Console.error ("Error:" <> show error)     -- proper Effect console

better :: Effect ()
better = Effect.logError error                    -- structured, with context

-- Why Effect logging
structured :: Effect () ∅
structured = do
  Effect.logInfo "Processing" `withLogSpan` "request"
  -- adds: timestamp, span, log level, structured context

-- Testable
test :: Effect () TestConsole
test = do
  program
  logs ← TestConsole.output
  assert (logs `contains` "expected message")
```

`console.*` in Effect code breaks the paradigm. Use `Console` service or `Effect.log*` for structured, testable logging.