Senior LLM Engineer (Remote, Mexico City)

Blacksmith Agency is building AI into every part of how we work. As Senior LLM Engineer at Blacksmith, you own and ship our internal automation roadmap: production LLM and agent systems that real people on our team use every day. This is a builder role, not research. You will not train models.

We hire engineers who have already shipped an LLM system to production and can walk us through it in detail: what it did, how it was built, what broke and what they changed. This is a full-time seat and it has to be your only job.

What You Will Build

• Agents and workflows with tool use and function calling on Anthropic and OpenAI, with a framework or plain APIs.
• Evals that prove a change made things better, and guardrails that stop a model taking a wrong or unsafe action.
• Integrations connecting WordPress, Figma, Google Workspace, Slack and our internal systems, including MCP servers.
• Internal tools that take measurable hours off delivery, sales operations and project management.

• 2+ years building production software in Python or TypeScript / Node.js.
• At least one LLM or agent system you built yourself that ran in production with real users.
• Hands-on tool use, evals and failure handling: validating model output, retries, human approval.
• REST APIs, webhooks and cloud deployment.
• Strong spoken English. You will talk through technical decisions on live calls with a US team.