cost-accounting

cost-accounting is a skill for Claude Code from cbrock84/headcount. It costs 92 tokens per session (834 once invoked), scanned A, original, MIT.

A method for working out what products, services, or orders actually cost, including fixed costs, costs that change with volume, and shared production costs.

In plain words
What is it for?
It is for setting price floors, explaining margin changes, calculating break-even points, comparing make-or-buy choices, and assessing product lines.
Why use it?
It prevents pricing and product decisions from using the wrong definition of cost, which can make growth appear profitable when it loses money.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the finance plugin — 13 skills shipped together

Good fit It is for setting price floors, explaining margin changes, calculating break-even points, comparing make-or-buy choices, and assessing product lines.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cbrock84/headcount/cost-accounting
About the project

headcount is an organization of independently installable Claude Code plugins, each grouping skills for a department such as finance, security, or demand generation. Claude Code users install the departments they need and invoke their skills for specialized work; the catalogue entries are skills and related agent tooling from that organization.

cbrock84/headcount · 1,320 stars · on GitHub · cbrock84.github.io

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add cbrock84/headcount --skill cost-accounting
Clone the repo
git clone --depth 1 https://github.com/cbrock84/headcount

Made for: Claude Code.

Or install finance, the plugin that ships this one along with the rest of its 13 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for cost-accounting

README.md
[![agentmods](https://agentmods.dev/badge/skills/cbrock84/headcount/cost-accounting/github.svg)](https://agentmods.dev/skills/cbrock84/headcount/cost-accounting)
Your own site
<a href="https://agentmods.dev/skills/cbrock84/headcount/cost-accounting"><img src="https://agentmods.dev/badge/skills/cbrock84/headcount/cost-accounting/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for cost-accounting

Your own site · 80×15
<a href="https://agentmods.dev/skills/cbrock84/headcount/cost-accounting"><img src="https://agentmods.dev/badge/skills/cbrock84/headcount/cost-accounting.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 92 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 834 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 72
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00092 $0.00834
Opus 5 $0.00046 $0.00417
Sonnet 5 $0.00018 $0.00167
Haiku 4.5 $0.00009 $0.00083

Measured 5d ago against content hash 5af23a805aca, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

cost-accounting scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/finance/skills/cost-accounting/SKILL.md · 74 lines

How it starts

The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cost accounting

Most bad pricing decisions, bad product-line decisions, and bad margin arguments come from the same place: nobody agrees what the thing costs.

Classify cost behavior before you allocate anything

  • Fixed costs do not move with volume — within a relevant range. Outside that range they step, and the step is usually large: another shift, another facility, another tier of licensing.
  • Variable costs move with each unit: materials, payment processing, per-unit fulfillment, usage-based infrastructure.
  • Mixed costs have both, and most real accounts are mixed. Split them with high-low or a regression on historical volume rather than guessing the proportion.

The split is not academic. Variable cost sets the floor for one more incremental order. Fully loaded cost sets the floor for the business as a whole. Confusing the two is how companies price themselves into volume that loses money.

Know which costing basis you are looking at

Absorption costing puts fixed production overhead into inventory and releases it when the unit sells. Variable costing expenses that overhead as incurred.

Absorption is what external reporting requires. Variable is what decisions want. The consequence worth carrying: under absorption, producing more than you sell moves fixed cost onto the balance sheet and raises reported profit without a single additional sale. When margin improves and inventory grows in the same period, check whether that is what happened.

Match the costing method to how the work actually runs

  • Job-order — distinct, identifiable jobs. Construction, custom manufacture, print runs, agency engagements. Cost accumulates per job.
  • Process — continuous, homogeneous output. Chemicals, food, high-volume components. Cost accumulates per period and divides across equivalent units.
  • Activity-based — worth the overhead when indirect cost is large and consumed unevenly. Its value is rarely precision; it is discovering that a low-volume product consumes a disproportionate share of support, setup, or handling.

Read the full file on GitHub · 74 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 74 lines · 92 tokens per session scan A 5af23a805aca

Subscribe to this mod's changes

cost-accounting is a skill published in the GitHub repository cbrock84/headcount (1,320 stars, last pushed 6d ago), licensed MIT. It adds 92 tokens to every session and 834 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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