# v0.8.1: the cost ABP gets its article, with six figures captured from the v0.8.0 tag

> One article per release, so the release that added the cost walkthrough gets one. It covers why cost is a property of every call rather than a capability, why the section is written over the runtime universe and says so on every page, why the fifth cost line is the reason the...

*Source: <https://abp.sgit.ai/versions/v0.8.1/index.html> · site v0.10.1 · this file is generated from the same content
as the page, so the two cannot drift. Every page on this site has a `.md` twin; internal links
below point at them.*

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[Home](../../index.md) / [Versions](../../versions/index.md) / v0.8.1

# v0.8.1: the cost ABP gets its article, with six figures captured from the v0.8.0 tag

One article per release, so the release that added the cost walkthrough gets one. It covers why cost is a property of every call rather than a capability, why the section is written over the runtime universe and says so on every page, why the fifth cost line is the reason the section exists, why a behaviour policy is what a skill runs inside rather than another skill, and why a limit over a number the agent cannot see is an expectation twice over. Six screenshots from a checkout of the v0.8.0 tag on the day it shipped.

| Field | Value |
|---|---|
| Version | `v0.8.1` |
| Date | 2026-09-22 |
| Commit | **`git rev-list -n 1 v0.8.1`**. The tag is the record: CI derives it from `admin/build/version.txt` and creates it on the commit whose subject carries `site v0.8.1:`. The hash is not written into [`versions/v0.8.1.json`](../../versions/v0.8.1.json), because a release commit cannot contain its own hash and reading it back from the tag made the build produce different bytes on a checkout with tags than on one without. |
| Reconstructed | no |
| Machine readable | [`versions/v0.8.1.json`](../../versions/v0.8.1.json) |

## What changed

- An article for v0.8.0, the twelfth in the section, with six screenshots and the two figures the walkthrough carries. It ends on what the release did not settle: nothing measured, placeholder numbers, no meter for a person's hour, no case running the prompts, and cost never becoming a node.

## What it was built against

- The v0.8.0 tag, checked out into a detached worktree and served locally, the same method as every other article's figures.

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*[Site index for agents](../../llms.txt) · [HTML version](https://abp.sgit.ai/versions/v0.8.1/index.html)*