Get started

Plain for AI agents

Plain is a collaborative B2B support platform with an AI-powered interface that consolidates support channels into one place. Support teams use it to manage customer conversations and issues. 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 PlainSee the 23 actions ↓
Customer supportAPI keyMCP + RESTplain.com
AUDIT LOG · PLAINPOLICY: acme-support
09:41:07 · claude · u_8f2read
plain.list_tiers
List Tiers✓ allowed · 212ms
09:41:08 · claude · u_8f2read
plain.fetch_tier
Fetch Tier✓ allowed · 164ms
09:41:09 · claude · u_8f2write
plain.create_thread
Create Thread✓ approved · approved by user
09:41:12 · claude · u_8f2destructive
plain.delete_user
Delete User✕ blocked · policy: deny
EVERY PLAIN CALL, ON THE RECORD
01 · USE CASES

What agents do in Plain.

01

Send a message on a support thread

Reply to a customer's open thread with an answer or status update.

02

Check a customer's open issues read-only

Look up a customer's fetched issues before responding to a new support request.

03

Delete a customer with approval

Remove a customer record only after a support lead confirms the account is closed.

02 · ACTIONS

23 Plain actions, graded by risk.

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

read

12

Look things up. Allowed by default.

  • plain.list_tiers
    List Tiers
  • plain.list_threads
    List Threads (Deprecated)
  • plain.get_customers
    Get Customers
  • plain.query_threads
    List Threads
  • plain.get_user_by_id
    Get User By ID
  • plain.get_thread_by_id
    Get Thread By ID
  • plain.get_customer_by_id
    Get Customer By ID
  • plain.list_customer_groups
    List Customer Groups
  • plain.get_customer_by_email
    Get Customer By Email
  • plain.fetch_tier
    Fetch Tier
  • plain.fetch_issues
    Fetch Issues
  • plain.fetch_company
    Fetch Company

write

8

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

  • plain.send_message
    Send Message
  • plain.create_thread
    Create Thread
  • plain.update_thread
    Update Thread
  • plain.update_company
    Update Company
  • plain.add_customer_to_group
    Add Customer To Group
  • plain.create_customer_group
    Create Customer Group
  • plain.upsert_customer
    Upsert Customer
  • plain.run_graphql_query
    Run GraphQL Query

destructive

3

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

  • plain.delete_user
    Delete User
  • plain.delete_customer
    Delete Customer
  • plain.remove_customer_from_group
    Remove Customer From Group
03 · HOW IT WORKS

Plain in three steps.

  1. 01Your users connect PlainThey add their Plain api key on Arc0 Connect, under your brand. It goes straight into the vault.
  2. 02You set the rulesReads run, writes like “create Thread” can wait for the user, and “delete User” can be denied outright.
  3. 03Any agent can actYour agent calls Plain 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('plain', {
  read: 'allow',
  write: 'ask',        // create_thread
  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 Plain connects.

Users add their Plain 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 Plain 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 Plain from any agent.

Claude
ChatGPT
Cursor
Codex
VS Code
OpenAI Agents SDK
Claude Agent SDK
Vercel AI SDK
Mastra
LangGraph
06 · RELATED

More customer support apps.

Intercom133 actionsGleap179 actionsHelp Scout129 actionsSupportbee41 actionsProductlane39 actionsHelpwise37 actionsFuseDesk27 actionsOnedesk24 actions
ALL CUSTOMER SUPPORT APPS →
07 · FAQ

Plain and Arc0, answered.

Q01

Can I use Plain with Claude, ChatGPT or Cursor?

Yes. Connect Plain 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 Plain actions you allow.

Q02

How do users connect Plain?

Users add their Plain 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 Plain actions can my agent take?

23 in total: 12 read, 8 write and 3 destructive, such as “create Thread”. Your policies decide which of them each agent may call.

Q04

Can I stop my agent from deleting things in Plain?

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 Plain too?

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

Get started

Plug Plain into your agent.

Your users connect Plain once, under your brand. Your agent gets 23 actions behind your policies, with every call on the record.

Connect PlainBrowse all apps →

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