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freelance ai systems engineer · ai agents · evaluation

Production-grade
AI agents,
built and measured.

I build AI agents that retrieve, reason and take action, and the evaluation layer that gates them: golden sets, regression tests in CI, tracing, guardrails. Built in your repo.

agent tracelive

An example run: the request is planned, context is retrieved, a tool is called, a critic checks the result against sources and policy, and the run passes the eval gate.

production AI, ML & data
7+ yrs
measure, then architect
eval-first
no handover cliff
your repo
aws · mlops
python · go · ts
Illustrated portrait of Rene Persau, smiling, in glasses and a hoodie, in front of monitors at night
02 · who you'll work with

Hi, I'm Rene.

I've spent 7+ years shipping production AI, ML and data systems in fast-moving startups: a multi-agent fraud detection system at Midnite, the evaluation framework and a $350K MRR AI product at Spotlight, and Perlego's first data platform as an early data hire.

Based in San Francisco, working remotely across EU and US hours.

More about me →midnite · spotlight · perlego · rainmaking
03 · stack

Works with the stack you already run

everything I use →
  • Python
    ml · fastapi
  • TypeScript
    web · tooling
  • Go
    services
  • Terraform
    aws · infra
  • LangGraph
    orchestration
  • pgvector
    vector search
  • OpenTelemetry
    tracing
  • MLflow
    experiments
  • Your repo, your CI.
  • No vendor lock-in.
  • Self-hosted models welcome.
04 · architecture

How it fits together

  1. Sources & index

    Documents, threads and records are chunked, embedded and tagged with metadata, so retrieval can filter before it ranks.

  2. Planner & specialist agents

    A planner breaks the request down and routes each part to a retriever, a tool or a critic, retrying when a step comes back thin.

  3. Traceable answers and actions

    Every claim points at the span it came from, and every action at the policy that allowed it.

  4. Guardrails & eval gate

    Policy checks and escalation paths wrap the whole flow, and a golden set in CI blocks any change that makes the agent worse.

reference architecture
Documents
policies, PDFs
Threads
email, tickets
Records
postgres, dwh
Ingestion & index
chunking · embeddings · metadata
Planner agent
decomposes · routes · retries
Retriever
hybrid + rerank
Tools
apis · actions
Critic
checks citations
Answer or action
cited · policy-checked
guardrails
policy · escalation
eval gate
golden set · CI
05 · evaluation

If it isn't measured, it doesn't ship.

  • Golden set from real traffic. Built from the questions your users actually ask, not the ones that demo well.
  • Gates every pull request. Prompt, model, retrieval and tool changes are scored in CI; a regression blocks the merge.
  • Traces you can read. When an answer goes wrong, you open the run and see which step failed.
How I measure →pytest in ci · your repo
~/your-repo
contact

Tell me what's breaking.

A few lines is enough. I reply within two working days, and if it isn't a fit I'll say so and point you somewhere better.

Where are you today?

sends straight to my inbox.

engineering@renepersau.comsan francisco · remote across eu & us hours