Handwrite.io for AI agents

Handwrite.io creates and tracks physical handwritten card orders, choosing from real handwriting and stationery styles. Marketers fold it into their existing outreach and campaign workflow instead of running it separately. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect Handwrite.io See the 4 actions ↓

MarketingAPI keyMCP + RESThandwrite.io

AUDIT LOG · HANDWRITE.IOPOLICY: acme-support

09:41:07 · claude · u_8f2read

handwrite_io.list_stationery

List Stationery✓ allowed · 212ms

09:41:08 · claude · u_8f2read

handwrite_io.get_order

Get Order✓ allowed · 164ms

09:41:09 · claude · u_8f2write

handwrite_io.send_cards

Send Handwritten Cards✓ approved · approved by user

EVERY HANDWRITE.IO CALL, ON THE RECORD

01 · USE CASES

What agents do in Handwrite.io.

Send a handwritten card

Send a handwritten thank-you card to a client using a chosen handwriting and stationery style.

Check an order's status

Look up a placed card order to confirm it has shipped before following up with the recipient.

Browse stationery options

List available stationery styles to choose one that matches a brand's tone.

02 · ACTIONS

4 Handwrite.io actions, graded by risk.

Every Handwrite.io action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

Look things up. Allowed by default.

handwrite_io.get_order
Get Order
handwrite_io.list_stationery
List Stationery
handwrite_io.list_handwriting_styles
List Handwriting Styles

write

Create and change things. Allow, or ask the user first.

handwrite_io.send_cards
Send Handwritten Cards

destructive

Delete, cancel or archive. Ask first, or deny outright.

No destructive actions.

03 · HOW IT WORKS

Handwrite.io in three steps.

01Your users connect Handwrite.ioThey add their Handwrite.io api key on Arc0 Connect, under your brand. It goes straight into the vault.
02You set the rulesReads run, and writes like “send Handwritten Cards” can wait for the user to approve.
03Any agent can actYour agent calls Handwrite.io through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.

POLICY.TS

await arc0.policies.set('handwrite_io', {
  read: 'allow',
  write: 'ask',        // send_cards
  destructive: 'deny',  
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2

04 · AUTH AND DATA

How Handwrite.io connects.

Users add their Handwrite.io api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same Handwrite.io connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH: API key
CREDENTIALS: Per-tenant encrypted vault
MODEL SEES: Results only, never credentials
AUDIT LOG: Every call, on every plan

05 · WORKS WITH

Use Handwrite.io from any agent.

Claude

ChatGPT

Cursor

Codex

VS Code

OpenAI Agents SDK

Claude Agent SDK

Vercel AI SDK

Mastra

LangGraph

06 · RELATED

More marketing apps.

Meta Ads67 actions

ActiveCampaign298 actions ActiveTrail159 actions

Adobe Marketing Agent12 actions

07 · FAQ

Handwrite.io and Arc0, answered.

Q01

Can I use Handwrite.io with Claude, ChatGPT or Cursor?

Yes. Connect Handwrite.io to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the Handwrite.io actions you allow.

Q02

How do users connect Handwrite.io?

Users add their Handwrite.io api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which Handwrite.io actions can my agent take?

4 in total: 3 read, 1 write and 0 destructive, such as “send Handwritten Cards”. Your policies decide which of them each agent may call.

Q04

Can I make my agent read-only in Handwrite.io?

Yes. Allow read actions and deny writes in the Handwrite.io policy. Your agent can still look things up, and any write it attempts is blocked and logged.

Q05

Can my own backend call Handwrite.io too?

Yes. The same Handwrite.io connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug Handwrite.io into your agent.

Your users connect Handwrite.io once, under your brand. Your agent gets 4 actions behind your policies, with every call on the record.

Connect Handwrite.io Browse all apps →

Free to build · MCP + REST · Audit log on every plan