Key Takeaways

  • Resend created an official suite of over 80 named Model Context Protocol (MCP) tools after an early prototype built by Yoko Li from Andreessen Horowitz proved the concept.
  • Rocha rejected the standard advice to limit tool counts, finding that newer frontier models no longer get confused by large tool sets.
  • Modern full-stack frameworks like Next.js pushed developers to co-locate database queries inside UI components, accidentally starving products of headless APIs.
  • True agent accessibility requires 100 percent dashboard parity across MCP, REST APIs, and CLIs, forcing founders to expose internal operations like billing, invites, and account deletion.

The Accidental Death of Public APIs

For the past five years, modern web development shifted toward developer convenience at the expense of API surfaces. Frameworks like Next.js encouraged engineers to co-locate database queries directly inside front-end React components. Server actions made data fetching faster to ship, but they hid core business logic behind internal RPC calls.

If a human developer or an autonomous agent wants to interact with your product programmatically, those co-located queries are useless. As Swyx pointed out during the conversation: “In fact, you should just always have like completely headless back end and then your front end just happens to be one of many clients that connects to your back end.” (play from 44:44)

Rocha built Resend around that exact conviction. “I really think about these problems is like, okay, how do I want my product to be? Well, I want my product to be formless. Whatever they want to do with the product, it should be possible.” (play from 38:19) A formless product does not care if the caller is a browser, a terminal, or an autonomous script. Every capability must exist independently of the screen.

Why Context Bloat Is Yesterday's Problem

Early adopters of function calling and agent protocols warned that giving an LLM too many tools degrades performance. The common practice was defensive: expose three to five generic endpoints, compress parameters, and let the model figure out the details.

Resend took the opposite path. After investor Yoko Li from a16z built their initial MCP prototype, Resend expanded the suite to over 80 discrete, named tools.

“This was a bigger concern earlier like oh if you have way too many tools they get confused,” (play from 43:16) Rocha explained. “I don't see that as much anymore. And in fact we are just adding more to the MCP.” (play from 43:21)

Instead of making models assemble multi-step logic from vague endpoints, Resend gave them explicit tools for distinct operational tasks. The models handle the breadth easily, provided tool names and descriptions remain clear.

The Hard Work of True Dashboard Parity

Most developer tools stop their API coverage at the primary resource. For Resend, that would mean sending an email or checking delivery status. But human dashboards contain dozens of other workflows that agents will soon execute on behalf of users.

“Getting to 100% coverage of what your dashboard can do is actually very very difficult because now you're doing usage billing team invites account provisioning deletion should that be exposed as an API or not?” (play from 43:54) Rocha said.

If an agent cannot provision an API key, invite a contractor, inspect an invoice, or delete a stale domain, the automation breaks. The user is forced back into a manual browser session. Achieving complete parity requires treating internal operations with the same rigor as consumer endpoints, writing documentation and auth schemes for tasks that teams usually bury behind administrative dashboards.

What to Do With This

Audit your core application dashboard this week by listing every button, form, and settings toggle your users can click. Mark each feature that lacks a corresponding public API endpoint. Pick three non-core features (such as team member invites, API key rotation, or billing receipt retrieval) and build dedicated API and MCP tool endpoints for them by Friday.