How to Use Claude as a Controller: The Clara Skill Guide

Updated

If the CFO answers "what should we do?", the controller answers "here is exactly what happened, and it is correct." Using Claude as a controller means applying that precision habit to the close: holding the checklist, interrogating the variances, and turning a ledger into something the rest of the business can read. It structures and checks; it does not see your accounting system, and it is not accounting or tax advice. A qualified accountant still owns the books.

Updated 15 September 2026. Prices read from the live product page on the day of writing; the product page is always the authority if they ever drift apart.

Running a close that does not slip

Month-end is a sequence that goes wrong when a step is forgotten. The skill holds the close checklist - what gets reconciled, what gets accrued, what gets reviewed, in what order - so the process is repeatable and the close lands on the same working day each month instead of dragging into the next week.

The useful version of that is not a list of tasks. It is a list with an owner, a dependency and a definition of done against each line, because the step that slips is almost always the one waiting on someone who did not know they were the blocker.

Act as a financial controller. Build a month-end close checklist for [company type, e.g. a 40-person B2B SaaS company on accrual accounting, one entity, [currency]]. Return it as a table ordered by day of the close, with columns: - day (relative: D+1, D+2 ...) - task - owner role (not a name) - what it depends on finishing first - definition of done (what proves it is complete, e.g. "balance ties to bank statement to the cent") Rules: - Put reconciliations before accruals, accruals before review. - Mark every task that commonly slips with WATCH and one line on why. - Flag any task that cannot start until someone outside finance acts. - Do not invent a task for a system I have not mentioned: [list the systems you actually use].

Finding what does not tie out

Controllers live for the variance that should not be there. Give the skill this period against last, or actuals against budget, and it flags the lines that moved unexpectedly and asks the questions a sharp accountant would: is this a timing difference, a misposting, or something real? It does not fix the entry. It points you at the one that needs a look.

The trick is to make it rank by materiality and tell you what evidence would settle each one, so you are not opening twelve GL accounts to find the two that matter.

Here are two periods of P&L by account: [paste]. Here is the budget for the same period: [paste]. For every line where the movement is over [threshold, e.g. 10% or [amount]], output a row with: - account - the movement, in currency and percent - the three most likely explanations, ordered by how common they are in practice (timing, misposting, genuine change in the business) - the ONE document or report I should open to settle it - materiality: does this change the reported result enough to matter? Then list the accounts that did NOT move and probably should have, given [what you know happened in the business this period]. Do not guess the cause. Give me the question to ask and where to look.

Turning the ledger into something readable

The books are not the report. The skill drafts the management accounts narrative - what the numbers say in plain language, what changed, what to watch - so the rest of the business can act on figures they would otherwise skim. That hands neatly to the decision layer a CFO approach works at, and to the deeper read in our financial analyst guide.

Write the management accounts commentary for [month] for a non-financial audience: [who reads it, e.g. the founders and two department heads]. Figures: [paste the P&L and the key balance sheet lines]. What happened in the business this period: [paste, plainly]. Structure: 1. Three sentences a reader can stop at and still know how the month went. 2. What moved, and why - only the lines that changed the result. 3. What to watch next month, with the number that would prove it. Rules: - Use only figures I gave you. If a sentence needs a number I did not supply, write [NEEDS FIGURE] and carry on. - No adjectives about performance. "Revenue fell 8%" not "revenue disappointingly softened". - Say which movements are timing and will reverse.
The skill behind this guide
Clara - Controller AI Skill
Clara - Controller AI Skill
$19once, keep the file vs $0/mono subscription

Holds your close checklist, your coding conventions and your reporting format across periods, so month eleven is run the same way as month one. Works in Claude, ChatGPT, Gemini or Copilot. Not accounting or tax advice.

View Clara →

Documenting the "how we do this"

Good controllership is good process, and process needs writing down. The skill drafts the procedures - how revenue is recognised here, how expenses are coded, how the reconciliation is done - so the knowledge does not live only in one person's head and the next close can be run by anyone competent. The test of a written procedure is whether someone who has never done it can follow it without asking you a question.

Answering the auditor before they ask

The skill helps you anticipate the questions an auditor or reviewer will raise and assemble the explanation and trail in advance. Walking into a review with the answers already structured is the difference between a smooth one and a painful one. Ask it to go through your accounting policies and your period movements and produce the list of items a reviewer would stop on, with the supporting document named for each.

Why a skill beats a one-off prompt

Controllership is the same exacting process repeated every period, which is precisely where a loaded file earns its place. It holds your close checklist, your coding conventions and your reporting format, so each month is handled identically rather than reinvented. In this job consistency is most of what accuracy means: the same treatment applied the same way, so that a movement between periods is a real movement and not a change in how someone wrote it up.

Where this falls down

  • It cannot see your ledger. No connection to your accounting system, your bank or your billing platform. Everything it works on is something you pasted, so nothing it says about your books is knowledge until you have given it the numbers.
  • It will be confidently wrong. There is no tone difference between an answer it is sure of and one it invented. A plausible-looking journal treatment is not a verified one.
  • It does not know your jurisdiction unless you say so. Ask a general question and you will often get a US-flavoured answer. Name the standard you report under - IFRS, US GAAP, a local statutory basis - in the first line.
  • It is not current. Standards, thresholds and tax treatment that changed after the model's training cutoff are simply absent, and it will not warn you.
  • It cannot sign anything. No professional accountability, no indemnity, no standing with an auditor. The qualified human signs the accounts, and owns whatever the model produced along the way.
The boundary that matters. The skill structures, checks and explains. It must not be the final authority on the books, tax treatment or compliance. Treat it as the diligent assistant who keeps the process tight and flags the oddities, with a qualified accountant signing off. Used that way, a tidy, on-time close gets considerably less painful.

In summary

Use it for the four jobs that repeat every period: holding the close checklist, interrogating variances by materiality, drafting the management accounts narrative, and writing the procedures down. Give it the figures and the jurisdiction; never let it supply a number or a treatment you have not checked. Clara - Controller AI Skill is $19 one time, with a 30-day money-back guarantee. The wider finance and accounting collection holds 103 skills, including Victor for the CFO seat and Petra for FP&A.

Related Skill Guides

Skill file · works with Claude & ChatGPT

Clara - Controller AI Skill

One file that carries your close checklist, coding conventions and reporting format into every period, so the close is run the same way each month. Instant download, no subscription, 30-day money-back guarantee.

$19
Get the Clara skill →

KissMySkills is a marketplace of over 1,900 AI skills, 60+ prompt packs, 90+ agents & free tools for Claude, ChatGPT & any AI chat.

Put this into practice

Or get every skill with Unlimited See plans →

Frequently asked questions

Can Claude actually close the books?+

No, and it is worth being precise about why. It has no connection to your accounting system, your bank or your billing platform, so it cannot post an entry, run a reconciliation or see a balance. What it does is hold the process: the checklist with owners and dependencies, the questions to ask of a variance, and the narrative that explains the result. The posting and the sign-off stay with a qualified accountant.

What does a Claude controller skill actually produce?+

Four things that repeat every period. A month-end close checklist ordered by day, with an owner, a dependency and a definition of done against each line. A variance review that ranks movements by materiality and names the one document that would settle each one. A management accounts commentary written for non-financial readers. And written procedures - how revenue is recognised here, how expenses are coded, how the reconciliation is done.

Will it get the accounting treatment right?+

Not reliably, and it will sound equally confident either way. There is no tone difference between an answer it is sure of and one it invented, so a plausible-looking journal treatment is not a verified one. It also does not know your jurisdiction unless you say so - name the basis you report under, IFRS, US GAAP or a local statutory basis, in the first line of the prompt - and anything that changed after the model's training cutoff is simply absent.

Is this accounting or tax advice?+

No. This is operational support for the process around the books, not advice on the books themselves. The skill has no professional accountability, no indemnity cover and no standing with an auditor. A qualified accountant signs the accounts and owns whatever the model produced along the way.

Why buy a skill instead of just writing the prompt each month?+

Because controllership is the same exacting process repeated every period, which is exactly where a loaded file pays. It holds your close checklist, your coding conventions and your reporting format, so month eleven is run identically to month one. In this job consistency is most of what accuracy means: a movement between periods should be a real movement, not a change in how someone wrote it up.

How much does the Clara controller skill cost?+

$19, paid once, with no subscription and a 30-day money-back guarantee. You download the file and keep it. The wider finance and accounting collection holds 103 skills, including Victor for the CFO seat and Petra for FP&A, at the same price.

Does it work in ChatGPT as well as Claude?+

Yes. A skill is a structured instruction file rather than Claude-only software. In the Claude app you upload it under Customize then Skills. Skills need code execution enabled, under Settings then Capabilities. Anthropic's help centre currently lists Skills on Free, Pro, Max, Team and Enterprise, while its Academy tutorial lists Pro, Max, Team and Enterprise, so if you are on the free plan check Settings then Capabilities for your own account rather than trusting either page. Where the Skills menu is not available, or in ChatGPT, Gemini or Copilot, you paste the file's contents into custom instructions instead.

What should I never paste into it?+

Treat it as a deliberate decision rather than a default. Anything that identifies a customer, an employee or a bank account deserves redacting before it goes into a third-party AI tool, and on consumer Claude plans conversations can be used for model improvement unless you opt out in Privacy Settings. Many finance teams run the skill against a template or a redacted extract rather than the live ledger, which costs very little in review quality.

~/get-started

Skills that work. No fluff.

Browse every skill, prompt pack, and agent in the store.

Browse all skills →Or try the free tools