zwesty
Write-ups / Day 1 / Orientation
Day 1 · Thu, Oct 1 · Orientation

Welcome Robots

First contact with the Game Master API: start a challenge, read the reply, find where the answer comes back

Claude Homebase Both

Flags are shortened to their first 8 and last 4 characters because they're unique per team.

Challenge ID
welcome-robots (Single Solve only; no Time Trial or Mastery)
Solved
2026-10-02: started 18:53:16 UTC through the Game Master; flag submitted by Zwesty in CourseStack the same day (Correct, 10 points)
Player
Zwesty (solo), with Claude Code (Opus 5.5)

The challenge

An orientation lesson: start the challenge through the Game Master and follow what the reply says. The lesson page has its own CourseStack answer field, so the flag goes there rather than through the Game Master's submit.

Reading the prompt: what it said we'd need

Clue What it pointed to What I did about it
"Start it through the Game Master" The challenge exists only once started; status said start_required Started it through our Game Master client
A CourseStack answer field on the lesson page The answer is entered there, not via the Game Master Zwesty pasted the flag into the field himself

What came back

The start reply was the whole challenge. It returned result: issued with answer_ids: ["flag"], deadline: null, and the flag already filled in (issued_flag). There was no artifact to download and nothing to solve.

Single Solve

  1. 18:5x UTC: a status call for welcome-robots returned start_required, with no questions or files yet.
  2. 18:53:16 UTC: started over the Homebase relay (the first live use of our Game Master client). The flag came back in the reply: 9ab0e07b…c1ed.
  3. Zwesty submitted it in the CourseStack field: shown as Correct, 10 points, and the lesson ticked. It was not sent through the Game Master.

Time to solve

The challenge was started at 18:53:16 UTC on 2026-10-02 and the flag came back in that same reply; Zwesty entered it in CourseStack later the same day, and it was marked Correct on the first try.

Takeaways

  • Read the start reply in full. For orientation lessons the answer is in the reply itself (issued_flag).
  • Check where the answer goes. Lessons with their own CourseStack field are answered there, not with the Game Master's submit.
  • The first live run of our client worked. It confirmed the reply's shape (attempt_id, mode, started_at, result, answer_ids, deadline), which every later solver relies on.
  • Wait for SSH after a restart. The Homebase refused SSH for a few seconds after showing Running; wait for port 22 before connecting.