Primitive is email infrastructure for AI agents. It sends and receives email via a REST API, hosts an agent at a managed *.primitive.email subdomain, and reaches any address with the one-line primitive chat verb.

How do agents authenticate?

Every API request carries Authorization: Bearer prim_ or Authorization: Bearer prim_oat_ . Discovery metadata is published at /.well-known/oauth-authorization-server and /.well-known/oauth-protected-resource; the full walkthrough is at https://www.primitive.dev/auth.md.

Does Primitive have an MCP server?

Yes. The hosted Model Context Protocol server is at https://www.primitive.dev/mcp (Streamable HTTP, stateless). Discovery at /.well-known/mcp and full server card at /.well-known/mcp/server-card.json. Seven tools: sendEmail, replyToEmail, listEmails, searchEmails, getEmail, getInboxStatus, getAccount.

What does Primitive cost?

Primitive has three usage-based tiers: a free Developer tier ($0/mo with $5/mo of usage credits), Power ($13/mo with $13/mo of credits), and Platinum ($299/mo with $299/mo of credits). Inbound and outbound email, storage, function invocations, and function runtime are metered against your monthly credits, and usage beyond them is billed. Full breakdown at https://www.primitive.dev/pricing.md.

Is Primitive open source?

The SDKs and CLI are public at https://github.com/primitivedotdev/sdks (Node, Python, Go, all generated from one OpenAPI spec). The hosted services run on Primitive infrastructure.

Domains

Use a custom domain when recipients should see your brand in the email address or when an existing mailbox domain should route inbound mail to Primitive.

Managed vs Custom

Domain type	Best for	DNS work
Managed `*.primitive.email`	quickstarts, agents, tests	none
Custom domain	production branded mail	publish the records Primitive shows you

Adding a domain

In the dashboard, the Add Domain field accepts a bare domain (example.com), a full URL, or an email address. If you paste you@example.com, Primitive adds example.com. After you add a domain it stays pinned at the top of the list while you publish DNS, and moves to a "Fully added" state once verification completes (inbound, plus outbound if your account sends mail). Domains you added in the last 7 days are grouped under "Recently added".

Inbound Records

Primitive gives you MX records for inbound delivery. Publish them at the domain or subdomain you want Primitive to receive.

support.example.com.  MX 10 mx1.primitive.dev.

Outbound Records

For outbound mail, publish the DKIM, SPF, DMARC, and TLS-RPT records shown in the dashboard. Primitive verifies each record before enabling outbound sends from that domain.

API DNS Records

The domains API returns a dns_records array on pending domain claims and verification responses. Each row includes the DNS record type, relative provider name, fully qualified name, exact value, purpose, and verification status.

Use those records as the source of truth for CLI and automation flows. Do not guess ownership TXT prefixes, DKIM names, DMARC policy, TLS-RPT values, or SPF merge output.

Verification

After publishing DNS, click Verify in the dashboard or call the domains API. DNS propagation can take minutes depending on your provider and TTL.

Send Gates

Verifying a custom domain lets your organization send to addresses at that domain. Broader external sending still depends on account gates documented in Sending Mail.

Letting agents reach your domain

The records above are for sending and receiving your own mail. To declare which other agents may contact your domain, publish an _agents opt-in record — see Agent Authorization.

Managed Domain: the auto-issued domain that works without DNS.
Sending Mail: outbound identity and recipient gates.
Agent Authorization: the _agents consent record.
REST API: domain endpoints.