Use the AI agent in Excel

Deckary's Excel AI agent completes multi-step workbook tasks by reading the relevant sheets and ranges, planning a target state, writing native Excel content, and observing the result. It can continue across several tool calls in one run instead of returning only a formula suggestion for you to paste manually.

What the agent can read#

The Excel agent can inspect:

• the current selection;
• a bounded workbook and worksheet summary;
• an explicit range as compact CSV;
• cell values, formulas, number formats, notes, and bounded style details;
• formula-audit findings for a specified range.

Selection previews are deliberately bounded. Large or style-heavy ranges require explicit range reads so the agent does not treat a truncated preview as the complete workbook.

What the agent can write#

The agent can write values and formulas to explicit cells, copy a bounded range, add notes, apply number formats and styles, create a worksheet, and set a worksheet tab color. It can also use a guarded Office JavaScript escape hatch for an operation that the normal tools do not express.

The escape hatch is not proof by itself that a workbook mutation succeeded. Deckary only treats an arbitrary operation as verified when the host can capture a supported target before and after the call and observe the expected change.

Write formulas safely#

Ask for formulas in terms of business logic and identify the input and output ranges. For example:

On Forecast, calculate monthly gross profit in row 24 from revenue in row 18
and cost of sales in row 21. Use formulas through column N, preserve the current
number format, then read back the result cells and formula text.

If target cells already contain values or formulas, Deckary may require explicit overwrite approval. That approval is bound to the observed target state.

Create and format a worksheet#

For a new tab, describe its role and minimum structure. The agent can create the sheet and then populate it with headers, labels, formulas, notes, borders, fills, and number formats. It should build workbook-native structure rather than placing a visual imitation over the worksheet.

Completion and verification#

A successful tool call is observed by the shared Office run before the agent can report the task complete. If a host write committed but readback failed, Deckary retains that partial truth and reports a verification issue. It does not reduce the event to “nothing happened” or claim that an unobserved result is correct.

For formula-specific checks, use Audit formulas. For a model-building pattern, see Financial modeling in Excel.