Task tool always fails with code invalid_type for subagent_type path

[teynar]

Steps to reproduce:

1 - Create a new docker container with an ubuntu base image

docker run --rm -it ubuntu:24.04 /bin/bash

2 - Input the following commands

apt-get update
apt-get install -y curl unzip
useradd -m -s /bin/bash john
su john

cd

curl -fsSL https://opencode.ai/install | bash
curl https://cursor.com/install -fsS | bash
echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.bashrc
source /home/john/.bashrc
mkdir project && cd project

# Go to https://cursor.com/dashboard/cloud-agents#my-secrets
# and generate an api key (since browser auth won't work here)
# replace the api key you obtained here
export CURSOR_API_KEY="xxxxxxxxxxxxxxxxxxxxxxxxxxx"

# Click on [a] Trust this workspace, then type /exit
cursor-agent

curl -fsSL https://bun.sh/install | bash
source /home/john/.bashrc

curl -fsSL https://raw.githubusercontent.com/Nomadcxx/opencode-cursor/main/install.sh | bash
cursor-agent models

# Switch model to Cursor/composer-2 by typing /models and then choosing it
opencode

Then type the prompt: Spawn an agent that sleeps for 10 seconds and then returns the message KOWABUNGA

This is the result I get:
session-ses_2c17.md

Constantly seeing this error message and it never works:

The task tool was called with invalid arguments: [
  {
    "expected": "string",
    "code": "invalid_type",
    "path": [
      "subagent_type"
    ],
    "message": "Invalid input: expected string, received undefined"
  }
].
Please rewrite the input so it satisfies the expected schema.

[Divkix]

I am having the same issue, will try to look into it later if I can fix and open a pr else if someone else can look, much appreciated.