AI engineering for production.

We help ship AI past the demo, into systems your customers depend on, your budget can sustain, and your team can still understand six months later.

For engineering teams who care what happens after the launch.

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Engagements

Every engagement is principal-led. No pyramids, no juniors, no handoffs.

Agent Architecture & Deployment

Agent architecture from design through production. Failure mode analysis, tool integration, observability, evaluation harness, and deployment. Whether that means reviewing an existing system or building it right the first time.

For teams moving agents from prototype to production.

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Agent Governance & Production Controls

The engineering layer underneath AI governance. Agent identity and credential delegation, scoped access, runtime guardrails, and eval pipelines that double as audit evidence. Controls implemented in code, mapped to EU AI Act, ISO 42001, or NIST AI RMF as outputs.

For teams whose compliance team is asking questions engineering can't yet answer in code.

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AI Cost Optimisation

Where your AI spend is coming from and how to bring it down. Token-level analysis, model routing, prompt efficiency, caching, local vs cloud inference evaluation, and implementation of the changes that move the needle.

For teams whose AI costs have outgrown their forecasts.

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Fractional Principal Engineer / CTO

AI-aided development coaching for your engineering team, plus principal-level judgement on tap for everything else. Architecture reviews, technology evaluations, executive briefings, and async availability for the questions that don't justify a full-time hire.

For teams getting serious about AI-aided engineering, without the full-time hire.

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What we work on

Two angles, one practice. From evals that aren't vibes to code your team still understands.

Shipping AI

For systems with an LLM in the running path.

  • Evals that aren't vibes
  • Agent identity, credentials, and runtime guardrails
  • Agent architectures that survive contact with real users
  • FinOps and cost discipline for AI workloads

Shipping with AI

For engineering teams whose own code is increasingly written with AI.

  • Engineering practice that levels up
  • Code review that keeps pace with AI
  • Code your team still understands
  • Team adoption that compounds

A principal-led consulting practice.

Founded by Wille Faler, Principal Engineer with 20 years of building production systems at banks, fintechs, and startups.

Most AI consulting is sold by partners and delivered by juniors. This isn't that. Engineering judgement from people who've shipped what you're trying to ship.

Designed to deliver results, not billable hours.

Not ready to talk?

Read what we think first. The Principal Engineer is where we write about evals, costs, code quality, and everything that breaks after the demo. Twice a week.

Visit principalengineer.com