Mark Lummus

Roadblock Title:

Before You Build an MCP: Lessons from Making a Fintech API Legible to Coding Agents

Time:

Tuesday - 10:30 AM (Windows)

Abstract:

Coding agents are starting to write fintech integrations, but they do not always behave like developers reading the latest docs. In our work making our API easier for agents to use, we saw agents mix current and legacy patterns, guess at auth flows, mishandle retries, and get stuck on errors that human developers could work around. We shipped an MCP server, but it did not solve the core problem. Instead, the engineering path forced a more basic question: what makes a fintechAPI legible to an agent in the first place?

This session walks through the practical journey that led us to an agent-readiness ladder: what prompted the work, what we tried, what failed, what surprised us, and how we changed our approach. We will cover concrete lessons around actionable errors, OpenAPI contracts, deprecation guidance, agent instruction files such as llms.txt, SKILL.md & AGENTS.md, and when MCP is actually the right answer. The focus is on coding agents that build integrations, not autonomous payment agents that move money.