# Why two agents never share a file

Status: DRAFT, nothing posted. Single-image infographic, 1 slide(s), no cover. Idea IB-0170.

## What it shows

The partition rule for parallel agents: a shared output file turns parallel work into serial work, so each agent gets its own file.

No numbers appear on the slides unless listed below.

## Claims and sources

| Claim | Source (agency-operator unless stated) | Read-date |
|---|---|---|
| Two agents on the same file: one quietly undoes the other; the rule is non-overlapping outputs | IB-0170 hook line; `.claude/rules/08-model-routing.md` (fan-out step 1: no two agents ever edit the same file) | 2026-10-11 |
| Shared state or coordination work is capped at 3 to 4 agents | `.claude/rules/08-model-routing.md` (caps table) | 2026-10-11 |
| Confirm no two items resolve to the same output path | `.claude/skills/fan-out/SKILL.md` (Process step 1) | 2026-10-11 |