---
title: "Write down the load you plan for · Agent Wranglers"
url: https://agentwranglers.se/playbook/scaling/measure-before-you-scale/load-model
updated: 2026-10-21
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Write down the load you plan for

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Measure before you scale](https://agentwranglers.se/playbook/scaling/measure-before-you-scale.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers). Updated 2026-10-21.

- ID: SCL-3
- Level: Recommended
- Chapter: [Measure before you scale](https://agentwranglers.se/playbook/scaling/measure-before-you-scale)
- Rule: Keep one written load model in the repository. It states the peak requests per second on the busiest routes, the share of writes, the data size and the growth expected over 12 months.
- How: Take today's numbers from [rate, errors and duration](https://agentwranglers.se/playbook/operations/metrics-and-traces/red-metrics). Use the busiest 5 minutes of the busiest day, not the daily average. Add known events, such as a sale or a newsletter send. Give the [load test](https://agentwranglers.se/playbook/testing/non-functional-tests/load-tests) the same mix of routes, so it does not test the home page alone. The [headroom](https://agentwranglers.se/playbook/operations/capacity-and-cost/headroom) target compares against this peak. Update the model when traffic passes its forecast by 50%.
- Check: The load model file is dated within the last 6 months. The share of each route in the load test script is within 10 percentage points of its share in the model.

## Examples

**Using these examples:** they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

### YAML example

```yaml
# load-model.yaml for a made-up shop at shop.example.com
measured: 2026-10-01
peak_window: busiest 5 minutes of the last 30 days
routes:
  - { route: GET /products/:id, peak_rps: 180, share: 0.60 }
  - { route: GET /search, peak_rps: 60, share: 0.20 }
  - { route: POST /cart, peak_rps: 45, share: 0.15 }
  - { route: POST /checkout, peak_rps: 15, share: 0.05 }
data: { orders_rows: 4_200_000, database_gb: 38 }
growth_12_months: 2.5x
events: [ "Black Friday: 4x normal peak for 6 hours" ]
```

## Related rules

- [Measure rate, errors and duration](https://agentwranglers.se/playbook/operations/metrics-and-traces/red-metrics) in Operations
- [Test load against a budget](https://agentwranglers.se/playbook/testing/non-functional-tests/load-tests) in Testing
- [Keep headroom](https://agentwranglers.se/playbook/operations/capacity-and-cost/headroom) in Operations

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/scaling/measure-before-you-scale/load-model">Agent Wranglers scaling playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Profile the slow path before you change it](https://agentwranglers.se/playbook/scaling/measure-before-you-scale/profile-first)
- Next: [Size workers and pools from rate times duration](https://agentwranglers.se/playbook/scaling/measure-before-you-scale/size-from-rate-and-duration)
- [Measure before you scale](https://agentwranglers.se/playbook/scaling/measure-before-you-scale)