SENIOR AI ENGINEER @ FYLD · UK

AI agents you can
measure and trust.

I build production agent systems — and the unglamorous infrastructure that tells you whether they actually work: tracing, evals, reliability. Outside work I run small, careful experiments on how models learn and how we evaluate them.

sam@ai:~

$ whoami

senior_ai_engineer

$ focus

production_agents
llm_observability
evals
judge_reliability
architecture_research
interpretability

$ now

self-organising-transformer: attempt 9
meta-eval: building the judge panel

$ policy

honest numbers only_

01

What I work on

01

Production agents

Agent platforms that hold up with real users: tracing on every LLM call, prompt versioning, PII masked before anything leaves the service, retries and model fallback. And deleting LLM calls that don't need to exist — if the model has no real decision to make, it's an if-statement.

Google ADKLangGraphLangfuseOpenTelemetry
02

Evaluation

LLM-as-judge evaluators, golden sets and functional tests — then the awkward follow-up question: how far can you trust the thing doing the grading? I write the grader before the model.

LLM-as-judgeJudge biasSafety evals
03

Model research

Small, controlled experiments on architecture and interpretability: dense baselines, multiple seeds, ablations. I publish the negative results too, because that's usually where the interesting part is.

PyTorchTransformersAblationsInterpretability
04

AI-native engineering

Running AI coding agents like a team: specs, plans, isolated worktrees, review gates and written rules for every failure. The skill isn't typing — it's framing, delegating and verifying.

Claude CodeReview gatesSpecs
02

Current research

All repositories ↗
ARCHITECTURE RESEARCH · ACTIVE

Self-Organising Transformer

Can a Transformer learn its own structure while it learns its weights — which layers, heads, FFN groups and skip edges to keep — and end up cheaper than a dense model of the same quality?

Honest status: not yet. The gated models still trail a dense baseline, and I retracted an early "beats dense" result after tracing it to a library bug that broke checkpoint loading. The useful finding: a gate's size doesn't tell you how important a unit is (layer gates correlate at ρ = −0.72 with real importance; a Taylor estimate gets 0.93). Next up: a Phase 2 run (discrete birth and death of units) with a fix that stops dormant units quietly propping up the numbers.

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EVALUATION · SAFETY · BUILDING

meta-eval

A harness that measures how fine-tuning and quantisation change model safety, and evaluates the evaluators: are common LLM-as-a-judge models biased on safety-critical tasks? A self-audit already caught judges sharing weights with the models they scored. No results yet — the full judge run is next.

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INTERPRETABILITY · WORK IN PROGRESS

Model Understanding

Tools for poking at what transformers attend to and why: saliency maps, integrated gradients, logit lens and attention rollout across classification, generative and seq2seq models.

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COMPUTER VISION · EXTENSION

DiffVax extension

Extending the authors' ICLR 2026 image-immunisation method to SD3.5 and FLUX. Verification tests caught silent training bugs — severed gradient paths and an inverted loss term — that produced plausible loss curves and zero signal. Verified on CPU; GPU validation pending.

↗

Older experiments: ELECTRA pretraining in PyTorch, GNN experiments and neurosymbolic language modelling. Some are polished; others are just me answering a technical question by writing code.

03

Experience

2026 → present

FYLD

Senior AI Engineer

Technical owner for 7 customer-facing production agents behind a construction-safety product. I wrote the AI platform strategy in my first three weeks — trust first (observability, evals, PII), then extensibility — and have spent the months since building it. Took the platform from zero observability to full tracing, prompt versioning and LLM-as-judge evals, with PII masked before export and separate EU/US data residency. Cutting LLM calls on one agent's first message from 9–12 to 3–4 took its average response time from over a minute to about 20 seconds. Retries and multi-model fallback took daily agent errors from hundreds to single digits. I also mentor, interview and review a lot of PRs.

2021 → 2026

Searchlight Cyber

Python Developer → Engineering Manager, AI

Built the company's AI capability from nothing: NLP and translation models, 30+ computer-vision models, and a customer-facing deep-research agent over 400M+ records, with a 28-query, 6-dimension evaluation suite to prove it worked. Scaled document throughput from ~10/s to tens of thousands per second. Then led a small AI team, before choosing to go back to hands-on technical ownership.

2020 → 2021

Harwin

Software Programmer

Robotics PLC logic and computer-vision inspection tools for high-precision manufacturing. Rewrote the flagship inspection programme in six months: +166% machine efficiency.

04

About

Software engineer turned AI engineer, with a habit of going one layer deeper than strictly necessary.

I studied Software Engineering at the University of Portsmouth and started out on automation and computer vision. From there I moved through ML engineering into LLMs, agents and production AI — and spent a stint managing an AI team before deciding I wanted my hands back on the hard problems.

What I care about: evidence over assertion, simple systems, honest numbers, and using code when the model has no real decision to make. Increasingly, that means evaluation — most people can build an agent, fewer can tell you how much to trust the thing that grades it.

GET IN TOUCH

Want to talk evals, agents or
research that didn't work?