Reply.io for AI agents

Reply.io automates multichannel sales outreach, letting teams build sequences, connect email accounts, and track contact status across campaigns. 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 Reply.io See the 33 actions ↓

MarketingAPI keyMCP + RESTreply.io

AUDIT LOG · REPLY.IOPOLICY: acme-support

09:41:07 · claude · u_8f2read

reply_io.list_lists

Reply.io List Lists✓ allowed · 212ms

09:41:08 · claude · u_8f2read

reply_io.list_sequences

List Sequences✓ allowed · 164ms

09:41:09 · claude · u_8f2write

reply_io.create_contact

Create Contact✓ approved · approved by user

09:41:12 · claude · u_8f2destructive

reply_io.delete_user

Delete User✕ blocked · policy: deny

EVERY REPLY.IO CALL, ON THE RECORD

01 · USE CASES

What agents do in Reply.io.

Add a contact to a sequence

Add a new lead to an outreach sequence after they're marked as a good fit.

Check a contact's status

Get a contact's current sequence status before deciding whether to follow up manually.

Confirm before deleting a sequence

Look up a sequence's steps and contacts first, then delete it only once approved.

02 · ACTIONS

33 Reply.io actions, graded by risk.

Every Reply.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.

reply_io.list_lists
Reply.io List Lists
reply_io.list_sequences
List Sequences
reply_io.search_contacts
Search Contacts by Email
reply_io.get_current_user
Get Current User
reply_io.get_contact_by_id
Get Contact by ID
reply_io.get_contact_status
Get Contact Status
reply_io.get_sequence_by_id
Get Sequence By ID
reply_io.list_contacts_basic
List Contacts Basic
reply_io.list_email_accounts
Reply.io List Email Accounts
reply_io.list_sequence_steps
List Sequence Steps
reply_io.get_sequence_step_by_id
Get Sequence Step by ID
reply_io.get_sequence_contacts_extended
Get Sequence Contacts Extended
reply_io.get_disconnected_email_accounts
Reply.io Get Disconnected Email Accounts

write

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

reply_io.create_contact
Create Contact
reply_io.update_contact
Update Contact
reply_io.create_sequence_step
Create Sequence Step
reply_io.update_email_account
Update Email Account
reply_io.add_contact_to_sequence
Add Contact to Sequence
reply_io.generate_ulid
Generate ULID
reply_io.pause_sequence
Pause Sequence
reply_io.start_sequence
Start Sequence
reply_io.set_contact_status
Set Contact Status
reply_io.connect_gmail_account
Connect Gmail Account
reply_io.connect_exchange_account
Connect Exchange Account via OAuth

destructive

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

reply_io.delete_user
Delete User
reply_io.delete_contact
Delete Contact
reply_io.delete_schedule
Delete Schedule
reply_io.delete_sequence
Delete Sequence
reply_io.archive_sequence
Archive Sequence
reply_io.delete_email_account
Delete Email Account
reply_io.remove_contact_from_sequence
Remove Contact From Sequence
reply_io.remove_contacts_from_sequence
Bulk Remove Contacts from Sequence
reply_io.clear_contact_status
Clear Contact Status

03 · HOW IT WORKS

Reply.io in three steps.

01Your users connect Reply.ioThey add their Reply.io api key on Arc0 Connect, under your brand. It goes straight into the vault.
02You set the rulesReads run, writes like “create Contact” can wait for the user, and “delete User” can be denied outright.
03Any agent can actYour agent calls Reply.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('reply_io', {
  read: 'allow',
  write: 'ask',        // create_contact
  destructive: 'deny',  // delete_user
})

# 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 Reply.io connects.

Users add their Reply.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 Reply.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 Reply.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

Reply.io and Arc0, answered.

Q01

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

Yes. Connect Reply.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 Reply.io actions you allow.

Q02

How do users connect Reply.io?

Users add their Reply.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 Reply.io actions can my agent take?

33 in total: 13 read, 11 write and 9 destructive, such as “create Contact”. Your policies decide which of them each agent may call.

Q04

Can I stop my agent from deleting things in Reply.io?

Yes. Actions like “delete User” are graded destructive. Set destructive actions to deny, or to ask so the user approves each one, and blocked calls still show up on the audit log.

Q05

Can my own backend call Reply.io too?

Yes. The same Reply.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 Reply.io into your agent.

Your users connect Reply.io once, under your brand. Your agent gets 33 actions behind your policies, with every call on the record.

Connect Reply.io Browse all apps →

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