stack-debug

# Stack Debugging

Troubleshoot @outfitter/* package issues.

## Result Issues

### Always Getting Error

**Symptom:** Result is `err` when it should be `ok`.

**Check validation:**
```typescript
const inputResult = validateInput(rawInput);
if (inputResult.isErr()) {
  console.log("Validation failed:", inputResult.error.details);
  return inputResult;
}
```

**Check async:**
```typescript
// BAD: Missing await
const result = getUser(id);  // Promise, not Result!

// GOOD
const result = await getUser(id);
```

### Type Narrowing Broken

**Symptom:** TypeScript doesn't know type after `isOk()`.

```typescript
// BAD: Reassigning breaks narrowing
let result = await getUser(id);
if (result.isOk()) {
  result = await updateUser(result.value);  // Breaks!
}

// GOOD: Separate variables
const getResult = await getUser(id);
if (getResult.isErr()) return getResult;
const updateResult = await updateUser(getResult.value);
```

### Error Type Lost

**Use `_tag` for narrowing:**
```typescript
if (result.isErr()) {
  switch (result.error._tag) {
    case "ValidationError":
      console.log(result.error.details);
      break;
    case "NotFoundError":
      console.log(result.error.resourceId);
      break;
  }
}
```

## MCP Issues

### Tool Not Appearing

1. Register before `start()`:
   ```typescript
   server.registerTool(myTool);
   server.start();  // After registration!
   ```

2. Check schema is valid Zod with `.describe()`:
   ```typescript
   const schema = z.object({
     query: z.string().describe("Required for AI"),
   });
   ```

### Tool Invocation Failing

1. Verify handler is async:
   ```typescript
   handler: async (input) => {  // Not sync!
     return Result.ok(data);
   }
   ```

2. Return Result, not raw value:
   ```typescript
   // BAD
   return { data: "value" };

   // GOOD
   return Result.ok({ data: "value" });
   ```

## CLI Output Issues

### JSON Not Printing

1. Force mode:
   ```typescript
   await output(data, { mode: "json" });
   ```

2. Check