# Extraction prompts
Source: https://docs.file.ai/extract/extraction-prompts

> Write field titles and descriptions that fileAI extracts reliably.

AI Schemas

# Extraction prompts

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Write field titles and descriptions that fileAI extracts reliably.

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fileAI fills each schema field by reading its title and description, so the description works as the field’s extraction prompt. A clear, specific description is the most direct way to improve a field that comes back wrong or empty. Before rewriting a prompt, check that the file itself reads well: a digitally generated PDF with selectable text beats a low-resolution scan. See [Prepare your files](/ingest/supported-files#prepare-your-files).

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How it works

Every field in an [AI Schema](/extract/ai-schemas) has a `title`, a `type` and a `description`. fileAI sends the description to the extraction model as the instruction for that field; when a field has no description, its title is used instead. You write prompts in two places:

*   **In the app:** click the sparkle icon next to a field in the **AI Schema** tab, describe how the field should be captured, then click **Run** and **Save**.
*   **Over the API:** set `description` on a field with `PATCH /v1/files/schema`, then re-fill the file with `PATCH /v1/files/schema/rerun`.

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Guidelines

Be explicit and specific

Name exactly what you want. Instead of “Extract important details”, write “The invoice number printed in the header, labelled ‘Invoice No.’ or ‘Inv #’”.

Refer to fields by their schema titles

When one description mentions another field, use the title as it appears in your schema, such as `Customer name`, not “name” or “client”.

Say what the allowed values are

For a fixed set of answers, list them: “Delivery status: one of shipped, pending, delayed.” Better still, make the field an `enum` with those values. See [Data types](/extract/data-types).

Set the format you expect

For dates: “The date received, as YYYY-MM-DD.” For yes/no questions: “Is the payment confirmed? Answer true or false.”

Resolve ambiguity

If a document has several candidates, say which one you mean: “Contract date: the date the contract was signed, not the date it was created.”

Give an example value

A short example of the expected output, such as “e.g. INV-2025-0042”, helps the model match the shape you want.

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Example

Field title

Weak description

Strong description

`Total amount`

Total

The final amount due including tax, from the line labelled “Total” or “Amount due”. Number only, no currency symbol.

`Contract date`

Date

The date the contract was signed by both parties, not the date it was drafted.

`Delivery status`

Status

Current delivery status. One of: shipped, pending, delayed.

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Related

## AI Schemas

Edit fields in the app or over the API.

## Data types

Pick the right type so values come back in the right shape.

[Previous](/extract/schema-locking)[

Data types

The field types a schema can use, and the shape each value takes in the API.

Next

](/extract/data-types)

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## On this page

*   [How it works](#how-it-works)
*   [Guidelines](#guidelines)
*   [Example](#example)
*   [Related](#related)