Founding Harness Engineer: Build AI Agent Runtime (Remote)

Bolder Apps; Argentina; Remote; ARS 181,747,000 - 272,620,000; Part time

Benefits offered by this job

Founding equity

Remote work from LATAM/EEA

Direct line to founder

Job summary

Bolder Apps is partnering with an early-stage startup building an AI coworker that lives inside team tools and actually gets work done. We’re seeking a senior Founding Harness Engineer to craft the layer that makes it behave, including context, prompts, tool choices, and safe completion.

This contract role offers a path to full-time once it proves itself. The position is remote from Latin America or Eastern Europe, with overlap with US Pacific time.

Qualifications

• Proven experience shipping tool-using LLM agents to real users in production.
• Strong instincts for agent initiative with measurable results.
• Hands-on experience building eval and regression suites for LLM behavior.
• Understanding of safe tool execution, prompt injection, and data risk in multi-tenant setups.
• Backend skills in Python or TypeScript including async jobs, retries, and state management.
• Ability to explain tradeoffs from prototype to production.
• Excellent written and verbal communication to explain decisions to founders/users.

Responsibilities

• Build the agent runtime: context, tool choice, approval waits, and when to act/ask/quiet.
• Write and tune system prompts; avoid unnecessary channel spam.
• Own the eval and regression harness; treat prompt changes as code and test accordingly.
• Make long-running tasks survive interruptions, retries, and flaky APIs.
• Impose guardrails: approval gates for risky actions and data separation.
• Collaborate directly with the founder and early users to ship observed behaviors.

Skills

LLM agent production

Agent initiative

Eval & regression suites

Safe tool execution

Prompt injection

Multi-tenant data risk

Python/TypeScript backend

Communication

Tools

Python

TypeScript

LLM tooling

Job description

Bolder Apps is partnering with an early-stage startup building an AI coworker that lives inside team tools and actually gets work done. We’re seeking a senior Founding Harness Engineer to craft the layer that makes it behave, including context, prompts, tool choices, and safe completion.

This contract role offers a path to full-time once it proves itself. The position is remote from Latin America or Eastern Europe, with overlap with US Pacific time.