Hand it the work.
Get back the file.

OpenIntern is an open-source agent for Excel, PowerPoint and Word. Describe the outcome and it builds the model, the deck or the memo, checks its own work, and keeps a journal so you can undo any of it.

Open source, Apache-2.0
Your own OpenAI or Anthropic key, or a local model
Mac first

Forecast revenue for 2027 to 2031 at the growth rate on the Inputs sheet.

Read Inputs!B3: growth 6.0%
Wrote 5 formulas in C3:G3
No error values. Formula family consistent
Linked G3 to slide 4 and the memo

	A	B	C	D	E	F	G
1	Revenue, $m
2	Year	2026A	2027E	2028E	2029E	2030E	2031E
3	Revenue	1,000	1,060	1,124	1,191	1,262	1,338
4	Growth	–	6.0%	6.0%	6.0%	6.0%	6.0%

PowerPoint · slide 4 Revenue reaches $1.34bn by 2031

Word · memo, ¶2

At 6% a year, revenue grows from $1.0bn to $1,338m in 2031.

Illustration of a task. Figures are an example, not a customer’s data.

The deliverable is the file, not the chat.

Chat is how you steer it. What you get back is a workbook with live formulas, a deck that follows your template, or a document in your house style. One conversation covers all three apps, and a figure agreed in the workbook stays linked in the deck and the memo.

ExcelModels and clean data

Three-statement models, DCF, LBO, variance and peer comparisons, built with formulas and labelled assumptions, not pasted results.
Cleans messy exports: duplicates, numbers stored as text, inconsistent categories. Deletes rows only after you confirm.
Traces #REF!, #VALUE! and circular references back to their cause.
Pulls in CSV, PDF and filings, and records where each imported number came from.

PowerPointDecks from your numbers

Builds a deck from a workbook or a memo: summary, KPI tiles, charts with a takeaway, tables, risks and next steps.
Follows the deck’s own template and theme.
Edits existing decks without losing content: splits crowded slides, fixes titles, refreshes figures.
Renders every slide and looks at it before it finishes.

WordMemos and reports

Writes and revises memos, reports and letters with real styles, tables, captions, footnotes and a table of contents.
Works through comments and tracked changes, replying on each thread.
Fills your templates in place.

It checks before it says done.

An intern who hands back a model with a broken total isn’t much help. Before OpenIntern reports a task as finished, it verifies the result in the file itself.

Totals tie. Subtotals, balance sheet and cash flow agree.
No error values in the cells it was asked to produce.
Formulas, not typed-in numbers. Figures it can’t source are flagged, not invented.
Consistent formula families. No row quietly breaking the pattern.
Periods and units match across sheets, slides and text.
Slides are rendered and inspected for overflow, overlaps and tiny fonts.

Every change can be undone.

Each edit is journaled with its before and after state. Undo works per task and checks for conflicts, so it never overwrites changes you made since. A copy of the file is saved before the first change.

Chat only: Reads and answers. Changes nothing.
Ask before edits: You approve each batch of changes.
Act: Proceeds, but confirms anything destructive or ambiguous.
Bypass: Opt-in. No pauses, for work you’ve already scoped.

Measured in the real apps.

These runs used native Excel, PowerPoint and Word for Mac, not a simulator, in October 2026. They are our own runs on samples, not an official leaderboard. Some tasks pass on one run and fail on the next.

Task set	GPT-6 Luna	Claude Sonnet 5.5
SpreadsheetBench Verified, 40-task sample	36/40	39/40
Deck tasks, our set of 10	9/10	9/10
Document tasks, our set of 5	5/5	5/5

Your key. Your machine.

The agent runs in a small server on your own computer. There is no OpenIntern account and no telemetry.

Bring your own model. OpenAI, Anthropic, Google, Azure OpenAI, OpenRouter and others, or a local model through Ollama or LM Studio.
Keys stay local. They are kept by the local server and never sent back to the add-in or written to logs.
Documents go only where you send them: to the model provider you chose. Turn on no-egress mode and only a local model can be used.
Document text can’t give orders. Instructions hidden in a cell, slide or web page can’t grant permissions or change what the agent may do.

Questions

Can I use it today?

Not yet. It is in pre-release and used daily on Excel, PowerPoint and Word for Mac. Join the waitlist and we’ll email you when the source and the installer are out.

Does it work on Windows or Office on the web?

Not yet. Mac is the only platform we have tested end to end. Windows and the web are next.

What does it cost?

The software is free and open source under the Apache-2.0 licence. You pay your model provider for what you use, or nothing if you run a local model.

Is it made by Microsoft?

No. OpenIntern is an independent project and is not affiliated with or endorsed by Microsoft.

Get the first release.

One email when the source and the installer are ready. Nothing else.

Hand it the work.Get back the file.