06-reference

agiledata my ai harness

2026-05-15·reference·source: AgileData (Substack)·by Shagility (Agile Data Limited)
harness-engineeringai-harnessagent-tooling-stackdora-define-once-reuse-oftenretro-loopagile-dataclaude-code

"My AI Harness" — @Shagility

Why this is in the vault

Title is a direct vocabulary match to RDCO's harness-engineering thesis. Author is an agile-coaching practitioner in the data-and-analytics space (Agile Data Limited) who arrived independently at the same word for the same construct: a reusable convention package that gives every AI coding session the same way-of-working, disciplines, guardrails, and patterns. This is the third 2026-05 sighting of "harness" as a load-bearing frame outside the original Anthropic/Tan/Pachaar lineage, and the first from the data-engineering practitioner community specifically. The convergence keeps stacking.

The core argument

The author treats the AI not as a stateless tool but as a persistent agent that needs identity and governance loaded at session start. They built a directory-based harness on their MacBook with a four-file identity layer (persona, policies, way-of-working, retro), a universal conventions file (CLAUDE.md) covering task tracking, commit discipline, definition-of-ready/done, press-release formats, t-shirt sizing, pre-push verification, and design-system compliance, plus an on-demand skills system triggered by keyword, plus a three-tier inheritance hierarchy (universal harness to family templates to deployed agents).

The load-bearing mechanism is the retro propagation flow: weekly retro entries get promoted to way-of-working once proven, then promoted again to the universal harness inbox for cross-agent adoption. Learnings compound only when a curator-reviewed pipeline exists from individual session friction up to universal rules. They followed a "Define Once, Reuse Often" (DORO) principle. They trialed existing harnesses first and rejected them as a mismatch. Explicit caveat that this is a working journey, not a tested pattern.

Mapping against Ray Data Co

Is this author's "AI harness" the same concept as RDCO harness-engineering? Yes — same concept, same construct, independent vocabulary convergence.

Concrete alignment:

The differences are mostly surface:

This is convergent evidence, not a new component to pilot. He validates the frame from the data-engineering side. He does not surface a specific architectural pattern we haven't already implemented or considered. The retro-propagation discipline he describes is interesting framing for the skillify loop, but we already do it; he just gives it a clean three-tier name.

Market-signal value: an established voice in the agile-data community publicly adopting "harness" as the noun. Worth tracking as a data point that the vocabulary is spreading beyond the original cluster. Not worth a pilot. Not worth a Sanity Check piece on its own (no original re-frame; we'd just be restating his version of our position).

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