The shared account, the distinct key
- date
- 20260811
- what happened
- Node0 chose one shared, root-equivalent operating-system account for every agent on the fleet rather than an account per agent or per role, to avoid encoding guesses about a fleet shape that was not yet known.
- what it cost
- A named, accepted risk. A leaked credential for that shared account from any host reaches everything the account reaches.
- what changed
- Attribution and revocation come from a distinct credential per agent landing in the one account, never from separate accounts; every later credential decision is downstream of that rule.
- the check now
- Per-agent keys and per-service token names distinguish agents even though the operating-system account does not, and a single agent's key can be revoked without touching the account.
Anyone building a fleet operated by several automated actors hits this question in the first week. Does each actor get its own operating-system identity, or do they share one? On 20260811 Christoph chose the second, on purpose. Building per-role privilege boundaries before the fleet’s real shape was known would have slowed every deployment and baked in guesses that would later have to be unpicked.
The trade-off was written down rather than hidden. Agents that share the account share its authority, and a single leaked credential from any host has a blast radius of everything that account can reach. That is accepted, not solved.
What the decision bought was attribution without isolation. It holds only because of a second rule that costs almost nothing to keep. No two agents ever share a private key or an API token, even though both land in the same account. Revocation is then per agent rather than per account, and so is the record of who did what. By the collection of 20260920 the fleet repository’s 2,024 commits split cleanly by author field between two AI agents and one human, which is the evidence that the attribution model works without operating-system separation.
The general form is worth separating from Node0’s particulars. A homelab-scale or small-team set of automated operators does not need per-role Unix accounts to stay attributable; it needs per-actor credentials landing in one account, and a standing refusal to let two actors ever hold the same one.
Source: node0 lessons v0.1, lesson 6.1. Sanitized: checklist v0.1, 20260921; internal domain, decision-document path; voice pass 20260921. Part of oznog.com/node0.