> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.meetgail.com/platform/workflows/core-concepts/starting-a-workflow/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.meetgail.com/_mcp/server.

# Starting a Workflow

> Define the information a run needs to begin, including optional file attachments.

Every run of a workflow begins at its Start node, and most workflows need some
information to work with: a customer's name, a policy number, an uploaded
document. This page explains how to describe what a run needs, so the right
information is there before any step runs.

## Describing the information a run needs

On the Start node you can define an input schema: a short list of the fields a
run expects. For each field you give a name and a type (text, number, and so
on), and you mark which ones are required. For example, a quote-intake workflow
might require a `customer_name` and an `email`, and accept an optional
`priority` number.

Defining these fields has two benefits:

* **Runs are checked before they begin.** If someone starts the workflow without
  a required field, or sends a number where text was expected, the run is turned
  away with a clear message instead of failing partway through.
* **The shape is documented.** Anyone starting the workflow can see exactly what
  to provide.

Defining an input schema is optional. A workflow with no schema accepts any
information, or none at all.

> **Note**
>
> Whatever a run is given becomes available to your steps as values on the Start
> node, so later steps can read `customer_name`, `email`, and the rest. See
> [Variables & Data Flow](/platform/workflows/core-concepts/variables-data-flow).

## Attaching files

A run can also start with files attached, such as a PDF application or a CSV of
contacts. Uploaded files are stored securely and made available to steps that
work with them, like the [Agent](/platform/workflows/node-reference/ai/agent), which can
read a document and answer questions about it.

A few limits apply to file uploads:

| Limit         | Value                                                                                      |
| ------------- | ------------------------------------------------------------------------------------------ |
| Files per run | Up to 10                                                                                   |
| Size per file | Up to 25 MB                                                                                |
| File types    | PDF, Word, Excel, PowerPoint, text, CSV, RTF, and common images (JPG, PNG, GIF, BMP, WEBP) |

## Ways to start a run

A workflow can begin in more than one way:

* **Manually**, by starting it yourself to try it out or run a one-off.
* **On a request from another system**, using a webhook. See
  [Triggers & Webhooks](/platform/workflows/core-concepts/triggers-webhooks).
* **On a form submission or a lead**, from a JotForm, a Google Form, or a
  Facebook lead form. See the same
  [Triggers & Webhooks](/platform/workflows/core-concepts/triggers-webhooks) page.
* **On a schedule**, so it runs automatically at set times.

However a run starts, the same input schema and file rules apply, so the
information reaching your steps is consistent.

## Related

#### [Triggers & Webhooks](/platform/workflows/core-concepts/triggers-webhooks)

Let an outside system start a workflow on demand.

#### [Testing & Debugging](/platform/workflows/core-concepts/testing-debugging)

Start a run yourself and watch it proceed step by step.

> Documentation for Gail, the AI platform for financial services. Learn how to set up GailGPT and Gail Agent to automate customer communications for insurance, banking, and finance.