MCP CLI Development Engineer Intern

Location: Remote / San Francisco, CA
Work model: Remote-first
Employment: Internship

About the role

Build the system, then prove it works. CaelumenAI is building the governed production layer for agent-native software. PERCO, our flagship product, turns agent output into a reviewable plan, a controlled release, and evidence of what happened. As an MCP CLI Development Engineer Intern, you will work directly on the PERCO CLI and its MCP integration surface: the developer experience that connects coding clients to the control plane. You will own small, real product slices across command design, client integration, reliability, documentation, and verification—from a clearly scoped problem through implementation, real-client testing, and an evidence-backed handoff. This is not an autopilot project. The tools should give agents useful context and safe, typed capabilities while keeping credentials, infrastructure authority, and final production decisions with people.

Responsibilities

• Build and improve the PERCO CLI and MCP connection workflow for coding clients
• Design clear, reliable command flows for login, project linking, MCP installation, configuration, and recovery from errors
• Implement and test developer-facing integrations across supported coding clients and real project environments
• Make tool contracts predictable: useful project context, explicit limits, safe typed inputs, and actionable error messages
• Automate repeatable checks with unit tests, integration tests, Playwright, command output, logs, and release evidence
• Investigate failures to root cause and ship durable fixes with regression coverage

Requirements

• One substantive developer-tool, CLI, integration, or open-source project you designed, built, tested, and debugged that you can explain in detail
• Working proficiency in JavaScript or TypeScript or Python, Git, and web or API fundamentals
• Comfort with command-line workflows, package tooling, configuration, and debugging across local development environments
• Ability to turn ambiguous developer feedback into a small, testable product improvement
• Comfort testing real user journeys, reading logs, and iterating until an integration works end to end
• Clear written communication and a bias toward ownership, careful judgment, and evidence

Nice to have

• Experience building with MCP, JSON-RPC, tool schemas, or agent integrations
• Experience with coding clients such as Claude Code, Codex, Cursor, or similar developer tools
• Experience publishing npm packages or building CLI setup, authentication, or configuration flows
• Open-source contributions, developer documentation, or a shipped tool that other people use

Benefits

• Direct mentorship on a real developer-facing product
• High ownership over scoped, end-to-end engineering projects
• Flexible remote collaboration with an option to work from San Francisco
• Work at the intersection of MCP, coding agents, cloud systems, and responsible delivery