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PKU559: Function Metadata Not Found

Error Message​

[PKU559] No function metadata found for '[functionName]'.

What Went Wrong​

Pikku couldn't find metadata for the specified function. This usually means the function isn't wrapped with pikkuFunc() or hasn't been properly registered during the inspection phase.

How to Fix​

Ensure Function is Wrapped with pikkuFunc​

import { pikkuFunc } from '#pikku'

// ❌ Wrong: Regular function
const myHandler = async (input: { name: string }) => {
  return { message: `Hello ${input.name}` }
}

// ✅ Correct: Wrapped with pikkuFunc
const myHandler = pikkuFunc(async (input: { name: string }) => {
  return { message: `Hello ${input.name}` }
})

Make Sure Function is Exported​

// ❌ Wrong: Not exported
const myHandler = pikkuFunc(async () => {
  /* ... */
})

// ✅ Correct: Exported
export const myHandler = pikkuFunc(async () => {
  /* ... */
})

Verify Function is in Scanned Directory​

Check your pikku.config.json:

{
  "srcDirectories": ["src"], // Make sure your function file is in here
  "outDir": ".pikku"
}

Common Scenarios​

HTTP Routes​

import { wireHTTP } from '@pikku/core/http'
import { pikkuFunc } from '#pikku'

// Define the function first
export const getUsers = pikkuFunc(async () => {
  return { users: [] }
})

// Then wire it
wireHTTP({
  method: 'get',
  route: '/api/users',
  func: getUsers, // Must reference a pikkuFunc
})

Channel Handlers​

import { addChannel } from '@pikku/core/channel'
import { pikkuFunc } from '#pikku'

// All handlers must be pikkuFuncs
export const handleMessage = pikkuFunc(async (msg: string) => {
  return { echo: msg }
})

addChannel({
  name: 'chat',
  onMessageWiring: {
    message: handleMessage, // Must be a pikkuFunc
  },
})

MCP Tools​

import { addMCPTool } from '@pikku/core/mcp'
import { pikkuFunc } from '#pikku'

export const calculateSum = pikkuFunc(
  async ({ a, b }: { a: number; b: number }) => {
    return { sum: a + b }
  }
)

addMCPTool({
  name: 'sum',
  description: 'Adds two numbers',
  func: calculateSum, // Must be a pikkuFunc
})

Debugging Steps​

  1. Verify the function is wrapped with pikkuFunc()
  2. Check exports - Make sure the function is exported
  3. Run npx pikku prebuild to regenerate types
  4. Check file location - Ensure it's in a scanned directory

Common Mistakes​

  • Using regular async functions instead of pikkuFunc
  • Defining the function inline in the wiring call
  • Not exporting the function
  • Typos in the function name reference
  • PKU236 - Missing Function Property