Engineering
Map the legacy repo before the agent edits a line
Agents love to skim old repos — that is where the guesses hide.
What hurt
klöss (@kloss_xyz) shared a paste-before-you-edit prompt for Opus, Astra, or Grok Bot on legacy code: map the codebase, trace what the task will touch, flag dead code and hidden side effects, and make no edits until you approve the map. Not affiliated with xAI.
What to install or create
Paste his quoted prompt as the first message before any edit session. Approve the map, then allow edits.
Bots
Legacy coder
Maps first. Edits only after you approve the map.
Plugins
GitHub
Optional
Routines
None on the first run. Watch one manual pass first.
The prompt
Map before edit (author-quoted)
Quoted from @kloss_xyz — as published. Do not invent a second system prompt.
Before we change anything, map this entire codebase. Trace every piece of code this task and session will touch, what depends on it, and what breaks if it changes. Flag any dead code, hidden side effects, and literally anything you're guessing about that's not proven by code reads and specific lines. No code edits until I approve the map manually.
First run
- 1Read https://x.com/kloss_xyz/status/2109747284044824692 (credit @kloss_xyz).
- 2Open the legacy repo with your coding bot.
- 3Paste his map prompt as the first message — before any edit.
- 4Review the map: dependencies, break risks, guesses vs proven lines.
- 5Approve the map, then allow the bot to edit.
Approval fence
Do not merge or deploy without your yes after the map.
What to tweak
Steal the map-then-approve gate. No code edits until the map is proven.
Source
klöss @kloss_xyz · Original post
Not affiliated with xAI. We did not write this prompt. Third-party template terms still apply.
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