Senior Software Engineer · Backend-focused Full-Stack · AI agent tooling and evals · Node.js · TypeScript · Python
Currently at Thoughtworks (remote from Brazil, UTC-3) · 5+ years shipping cloud-native systems for international clients.
I build backend-focused full-stack systems for a living and tools for AI coding agents on the side. I care about measuring those tools: retrieval quality in hitgate, and which tools an agent actually gets in decision-critic.
Day job is senior consulting at Thoughtworks (previously CI&T), on international teams with strict review cultures. Off-hours I run a homelab and a self-hosted Discord bot, and I publish developer tooling on npm and PyPI.
- decision-critic: a runtime probe showed a Claude Code denylist left 91 MCP tools in place, including one that runs shell commands. The empty allow-list resolved to 0.
- hitgate: hybrid retrieval reaches Hit@5 0.99 on a 99-case benchmark (BM25 alone: 0.91), with a label-free evaluation gate in CI.
- Backend for a global consumer brand's mobile app and personalization platform (Node.js, AWS Lambda).
- Lucky: staging and production deploys, a migration gate and mutation testing.
| Project | What it does | Stack | |
|---|---|---|---|
| decision-critic | A reviewer agent with no tools, on purpose. Portable spec, Claude Code adapter, and a probe that checks what the host actually resolves | Node.js · Claude Code |  |
| hitgate | Hybrid RAG evaluation harness: BM25 + dense + RRF retrieval, label-free eval, CI-ready | Python · Sentence Transformers · BM25 |  |
| Lucky | Self-hosted Discord music bot: Spotify stats, autoplay recommendations, React dashboard, moderation suite | TypeScript · Prisma · Discord.js |  |
| homelab | Self-hosted infra: Docker Compose, Caddy, Tailscale, Prometheus/Grafana, SOPS | Python · Bash · Docker |  |
| sharekit | Share your AI coding setup (CLAUDE.md, skills, cursorrules) with one command: npx @lucassantana/sharekit install lucassantana |
Node.js · CLI |  |
Additional private repos (finance tools, infra dashboards) available on request.
Backend and cloud: Node.js · TypeScript · Python · Express · AWS (Lambda, S3, API Gateway, SSM, CloudWatch, EventBridge) · PostgreSQL · Redis · Prisma · Docker · Cloudflare Workers and Pages · Serverless Framework
AI agents: Claude Code (subagents, hooks, skills) · MCP servers · RAG retrieval and evaluation
Frontend: React · Next.js · Tailwind CSS · Material UI
DevOps and observability: GitHub Actions · Jenkins · Jest · Mocha · Grafana · Splunk · Kubernetes (k3s) · SOPS/age · Tailscale · Caddy · Linux
- AWS Certified Cloud Practitioner
- Bachelor's in Computer Systems, FIAP (2025)
- Open-source collaboration on AI agent tooling, evals, or observability
- Architecture and system-design discussions. Happy to review or pair
Get in touch: lucas.diassantana@gmail.com · LinkedIn
