> ## Documentation Index
> Fetch the complete documentation index at: https://docs.custral.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AI Writing Assistance

> Summarize a thread, draft a reply from a short instruction, and rewrite your draft (translate it, change its tone, fix grammar, or adjust length) right inside the email composer.

Custral brings AI into the inbox the way Superhuman does: a short **summary** of
every substantial thread, a one-click **draft reply**, and one-tap **rewrites**
of the draft you're writing: translate, change tone, fix grammar, or adjust
length.

Everything the AI produces is **returned for you to edit**. Nothing is sent
until you send it yourself.

## How it works

Each feature sends only the **plain text** it needs (the thread, or your draft)
to an AI model and shows you the result:

* **Summarize** reads the whole thread and returns a one- or two-sentence gist.
* **Draft with AI** reads the thread plus an optional instruction and writes a
  reply in your voice.
* **Rewrite with AI** takes the draft you've written and applies a single
  transform: translate, tone, grammar, or length.

None of these write, send, or save anything on their own.

## Using it

### Summarize a thread

Open an email. For any thread with real substance, a short **Summary** appears
at the top of the conversation (right under the subject, above the messages)
as a few bullet points. Click **Summary** to collapse or expand it. Trivial
one-line emails are left alone.

### Draft a reply

1. Open a reply (or a new email).
2. In the composer toolbar, click the **wand** (**Draft with AI**).
3. Optionally type what the reply should say, e.g. *"politely decline and
   suggest next week"*. Leave it blank to let Custral write the most appropriate
   reply to the latest message.
4. Click **Generate**. The draft fills the composer, ready to edit and send.

### Rewrite your draft

With a draft in the composer, click the **pen** (**Rewrite with AI**) in the
toolbar and choose:

* **Translate →** pick a language (Spanish, French, German, Italian, Portuguese,
  Dutch, Japanese, Chinese).
* **Make formal** / **Make friendly**. Change the tone.
* **Fix grammar & spelling**: clean up mistakes without changing your meaning.
* **Make shorter** / **Make longer**, adjust the length.

The rewritten text replaces your draft in place. Rewrite is disabled until
there's something in the composer to rewrite.

## Troubleshooting

<AccordionGroup>
  <Accordion title="No summary appears for a thread">
    Summaries are shown only for threads with enough content. A single short message (like "ok, thanks") is left alone
    on purpose. Very short threads, or a thread whose summary couldn't be generated, simply show nothing rather than an
    empty box.
  </Accordion>

  <Accordion title="Draft or Rewrite shows an error">
    These call an AI model, so an occasional failure can happen. The error notification includes a **request ID**, use
    **Report this** to send it to us. Try again in a moment; your existing draft is left untouched on failure.
  </Accordion>

  <Accordion title="Rewrite is greyed out">
    Rewrite works on the draft you've written, so it's disabled while the composer is empty. Write (or draft) something
    first, then rewrite it.
  </Accordion>

  <Accordion title="The draft or rewrite got a fact wrong">
    AI writing is an aid, not a source of truth. Always read what it produced before sending, and correct anything wrong.
    Never send a date, price, name, or commitment you haven't verified.
  </Accordion>

  <Accordion title="Nothing happens / AI usage is exhausted">
    If your workspace's AI usage is temporarily exhausted (for example in a sandbox), the request is declined. Try
    again later.
  </Accordion>
</AccordionGroup>

## Related

* [Smart Compose](/comms/email/smart-compose): inline autocomplete as you type.
* [Compose & Send](/comms/email/compose): the composer these actions run in.
* [Templates](/comms/email/templates): reusable snippets for canned text.
* [Custral AI overview](/ai/overview): the broader AI features in Custral.


## Related topics

- [Notes](/blocks/embedded/object/notes.md)
- [Run a record's AI auto-fills](/api-reference/records/run-a-records-ai-auto-fills.md)
- [Sources](/ai/property-agents/sources.md)
- [Get started with Email](/comms/email/getting-started.md)
- [Modules](/ai/modules.md)