Case study

MEF — Metadata Execution Framework

NatWest (via Accenture) · Oct 2022 – Jun 2026 · Principal Engineer / Platform Owner

A declarative platform for regulated data delivery — one workflow model, generated Airflow/Spark artifacts, and governance enforced in CI.

Replaced team-specific workflow implementations with one governed platform model for delivery across multiple bank teams.

The problem

Many delivery teams were building data workflows independently: inconsistent Airflow and Spark implementations, duplicated patterns, governance and operational standards varying team by team. Hard to onboard new teams; hard to audit what ran where — in an environment where auditability is not optional.

The platform

I designed and led MEF as a declarative execution layer: teams model workflows in a DSL, while the platform validates them, resolves dependencies, packages and publishes releases, and generates runtime artifacts instead of relying on hand-written pipeline code.

I also exposed the platform through a FastAPI metadata API and an MCP layer, so AI assistants could discover and invoke governed platform capabilities instead of relying on ad-hoc integrations.

I drove adoption through workshops and cross-team enablement, and supported the 2026 handover to bank infrastructure ownership.

Declarative workflow model (DSL)
intent: flows, contracts, execution semantics
↓
MEF execution layer
validate models · resolve dependencies · package releases · publish artifacts
↓
Generated execution artifacts
Airflow DAGs · Spark workloads · deployment configs
FastAPI metadata API
discovery · metadata access · platform integrations
MCP capability layer
governed platform access for AI assistants
CLI tooling
local validation · packaging · publishing workflows
Delivery standards & governance
CI validation · golden paths · auditability

Outcomes

Why it matters for AI product work

MEF's metadata already described operators, parameters, and execution semantics — so exposing capabilities to AI assistants through a metadata API and MCP was a natural extension: governed discovery instead of every team wiring its own integrations. Intent (what) is separated from runtime (how) and infrastructure (where). The same pattern extends to AI systems: declarative capabilities, approved tools and models, generated configurations, and governance built in — whether the runtime is Airflow or an agent loop.

PythonFastAPIAirflowSparkAWSDSL designMCPTerraformCI/CD