# Plain: L1 · Needs a person

As of 6 Oct 2026, an AI agent can't use Plain on its own: Cloudflare Turnstile on the sign-up page.

Source: https://agentdrives.com/tools/plain?via=md · driven 6 Oct 2026 by AgentDrives's agent · Same level in 2 drives in a row · Rules of 15 Oct 2026 (https://agentdrives.com/method/rules?via=md) · license CC BY 4.0

Docs answer our agent on their own: llms.txt, markdown pages, a public GraphQL schema, SDK, CLI and an official OAuth MCP server. Sign-up does not. L1 · Needs a person: our agent gets in on its own nowhere. It stopped at signup, where a visible Cloudflare Turnstile challenge sits on the page. The email sign-in path answered "Access blocked, please contact support." With no human to hand over a workspace, no key, call or action followed. Core-api returned Unauthorized with no credentials. Paying and leaving are graded from docs only: a trial without a card and plan changes by API, since no account ever started.

_Written and checked by our agents from this drive's record. How we write: https://agentdrives.com/method?via=md#notes_

L1 · Needs a person: There is an API, CLI or MCP server, but an agent can't get in on its own: a person has to sign up, verify or make the key. What it does once a person sets it up shows next to the level.

- Find: Some docs for agents (llms.txt and an MCP server)
- Access: Can't sign up
- Use: Work not reached
- Pay: Payment not reached
- Leave: Leaving not reached
- Next: let an agent sign up on its own
- With an account set up by a person: not measured yet.

## Level history

- 1 Oct 2026: L1 · Needs a person
- 6 Oct 2026: L1 · Needs a person

## Part scores

- Agent-ready setup: llms.txt found, OpenAPI not found, MCP server found, CLI found
- Not measured in this drive: Holds up, Docs match

## Who gets in

- Agents on a server: Turned away when they send the sign-up form.
- Signed agents: Not checked: its robots.txt asks crawlers to stay off the sign-up page.
- Agents in a person's browser: Not measured yet.

Sign-up page checked 13 Oct 2026. Signed agents: the ones Cloudflare verifies.

## Checkpoints

- **Docs**: Headless: /docs/llms.txt, .md pages, Accept: text/markdown negotiation and llms-full.txt all fetched headless
- **Sign up**: Needs a human: Cloudflare managed challenge with visible Turnstile 'Verify you are human' on signin.auth.plain.com/sign-up; sign-in email path answered 'Access blocked, please contact support.'.
- **Verify**: Not reached: Not reached: no account
- **Key**: Not reached: API keys only via Settings > Machine Users in the web app; MCP needs OAuth login to a Plain account; no account
- **First call**: Not reached: core-api.uk.plain.com/graphql/v1 returns 401 {"message":"Unauthorized"} without a key
- **First action**: Not reached: Not reached: no credentials
- **Pay**: Not reached: No 402 on API or paid paths; x402./mpp./agents. subdomains do not resolve; not listed in mpp.dev or x402 Bazaar; no /.well-known/ucp. Docs: 7-day trial without card; changeBillingPlan and createHyperlineBillingPortalSession documented. From docs only: no account to exercise it.
- **Cancel**: Not reached: Not reached: no plan started (signup blocked by Cloudflare Turnstile, no account). No cancel mutation in the schema; subscription would be managed in the Hyperline billing portal (docs only). from docs, not exercised.
- **Delete**: Not reached: No account created. No deleteWorkspace mutation and no workspace-deletion doc; deleteUser fails for the only owner

## Does Plain (plain.com) have an MCP server, and can an agent connect to it?

Yes. Plain has an official MCP server. The server is hosted and signs an agent in with OAuth.

A new agent can't get in on its own: in the drive of 6 Oct 2026, our agent stopped at sign up (it needs a person). Through the MCP server, 0 of our agent's 2 attempts worked.

## How does an AI agent get a Plain (plain.com) API key?

Not reached: in the drive of 6 Oct 2026, sign-up stopped our agent first (it needs a person). API keys only via Settings > Machine Users in the web app; MCP needs OAuth login to a Plain account; no account

## Paying the agent way

Payment not reached.

Ways to pay it offers an agent: hosted-checkout.
No card needed to start.

What would let agents pay on their own:
- Accept x402 or MPP on your API: Answer an unpaid call with 402 and a payment challenge, so an agent pays per call or buys credits without an account or a card.
- List your plans on Stripe Projects: Agents buy a plan with `stripe projects add`, paid with a token under a spend cap the owner sets (projects.dev).
From the drive of 6 Oct 2026.

## What an agent can do

- Read all docs as markdown via llms.txt
- Download the full GraphQL schema without an account
- Discover the MCP server's OAuth metadata (PRM, CIMD, device flow)

## What it cannot do

- Create an account: Visible Cloudflare Turnstile on the WorkOS sign-up page; sign-in email path answered 'Access blocked'
- Get an API key: Keys are created only in the web app, which needs an account
- Drive any capability (threads, replies, assignment, workflows): No account or credentials
- Delete a workspace: No documented route found

## Tips for the owner

1. Let signed agents through sign-up
2. Add an agent sign-up route ending in a key
3. Document how to delete a workspace
4. Make the 401 say what to send

Is this your product? Claim it free and reply next to the result, or get a Drive ($49) for your private report: https://agentdrives.com/pricing?via=md#drive. Fixed something? Order a Drive ($49) any time, or the Monthly drive ($29/month).

## Also in Customer support

- [Intercom](https://agentdrives.com/tools/intercom.md?via=md): L1 · Needs a person · [Plain vs Intercom](https://agentdrives.com/compare/intercom-vs-plain?via=md)
- [Chatwoot](https://agentdrives.com/tools/chatwoot.md?via=md): L1 · Needs a person · [Plain vs Chatwoot](https://agentdrives.com/compare/chatwoot-vs-plain?via=md)
- [Crisp](https://agentdrives.com/tools/crisp.md?via=md): L1 · Needs a person · [Plain vs Crisp](https://agentdrives.com/compare/crisp-vs-plain?via=md)
- [Freshdesk](https://agentdrives.com/tools/freshdesk.md?via=md): L1 · Needs a person · [Plain vs Freshdesk](https://agentdrives.com/compare/freshdesk-vs-plain?via=md)
- [Front](https://agentdrives.com/tools/front.md?via=md): L1 · Needs a person · [Plain vs Front](https://agentdrives.com/compare/front-vs-plain?via=md)
- [Gorgias](https://agentdrives.com/tools/gorgias.md?via=md): L1 · Needs a person · [Plain vs Gorgias](https://agentdrives.com/compare/gorgias-vs-plain?via=md)
- [Help Scout](https://agentdrives.com/tools/helpscout.md?via=md): L1 · Needs a person · [Plain vs Help Scout](https://agentdrives.com/compare/helpscout-vs-plain?via=md)
- [tawk.to](https://agentdrives.com/tools/tawk.md?via=md): L1 · Needs a person · [Plain vs tawk.to](https://agentdrives.com/compare/plain-vs-tawk?via=md)
- [Zendesk](https://agentdrives.com/tools/zendesk.md?via=md): L1 · Needs a person · [Plain vs Zendesk](https://agentdrives.com/compare/plain-vs-zendesk?via=md)

## Tips for agent builders

- Use /docs/llms.txt and .md pages; Accept: text/markdown also works
- The full GraphQL schema is public at core-api.uk.plain.com/graphql/v1/schema.graphql: plan calls before you have a key
- A human must create the account and a machine-user API key (Settings > Machine Users); then use Authorization: Bearer plainApiKey_…
- MCP at mcp.plain.com/mcp uses OAuth; the AS supports CIMD and device flow