RelayWork
Vocabulary

Glossary of AI-era software delivery

The terms teams argue about, defined plainly. Opinionated where the honest answer is an opinion — a definition that refuses to take a position is not much use to anyone.

For the practice itself, start with spec-driven development.

The practice

Spec-driven developmentalso: SDD

Building software where the specification is the durable artefact and the code is downstream of it. The document is precise enough that a competent engineer — or agent — could implement from it and land somewhere you would recognise.

Not a return to waterfall: the loop is short and the specs are small. What changed is that generating code got cheap, so agreeing what to build became the expensive part.

Spec

One unit of work, carrying two documents: requirements (what and why) and implementation (how). Everything else — tasks, approvals, code refs, pull requests — hangs off it.

Requirements documentalso: product spec, PRD

The what-and-why half. Problem, who has it, what changes when it ships, what you are deliberately not building, and the hard rules.

Length is a feature. A reviewer who has to read 1,400 words to find the decision will skim, and skimming is how bad specs get approved.

Implementation documentalso: design doc, technical spec

The how half: approach, data model, API surface, failure modes, test strategy, slices, rollout. Written after reading the actual code, not from imagination.

Approval gate

A point a spec cannot pass until a named human approves it. The approval is bound to the document version they read — edit the document and the approval dies.

Without the binding, an approval is a timestamp on a document that has since changed, which is worse than no approval because it looks like one.

Slice

A piece of implementation small enough to be wrong cheaply — two days or less, one reviewable pull request. Agents will happily generate a week of work in one pass, which nobody reviews properly.

Outcome review

The stage after Released: did the thing you shipped do what the spec claimed? Most teams never close this loop, which is why the same mistake gets specified twice.

Audit trail

The append-only record of who moved a spec, who approved which version, and when. The thing that answers “who decided this?” six months later, when nobody remembers the meeting.

Code and review

Code refalso: linked code, code anchor

A GitHub permalink attached to a spec — repo, path, line range, commit — with a note saying why those lines matter. Rendered as source inline beside the document.

Blast radius

Code a change could break but does not touch. Marking it explicitly tells a reviewer where to look for second-order damage without reading the whole diff.

Draft PR

A pull request opened to explore rather than to merge: stubs, a shape, enough to discover the constraint nobody remembered. It informs the plan and should never be treated as evidence the work is done.

Prompt-to-PR

The pattern where a request goes to an agent and comes back as a pull request. Fast, and it skips the two questions that matter: was this the right thing to build, and did anyone agree to it?

Agents and protocols

MCPalso: Model Context Protocol

An open protocol that lets an AI agent read and write real systems — files, APIs, trackers — instead of being told the state of the world in every prompt.

Practically: the difference between an assistant you brief from scratch each time and one that can look things up and write back.

MCP server

A service exposing tools an agent may call. A well-designed one is defined as much by what it omits — RelayWork has no approve tool at all, so no misconfiguration can let a machine sign off its own work.

Tool scope

Whether a token may read or also write, and which tools it can reach. Scoped, revocable tokens are what make agent access auditable rather than a shared password.

Machine attribution

Recording an automated write as the token that made it rather than as a person. Without it, an agent’s edit silently borrows a human’s authority.

Agent

A model given tools and a goal, running a loop rather than answering once. The useful distinction from a chatbot is not intelligence — it is that an agent changes state in systems you care about.

Vibe coding

Building by describing what you want and accepting what comes back without reading it closely. Genuinely fine for a prototype. The failure mode is shipping it, then discovering nobody — human or model — knows why the code does what it does.

Context engineering

Deciding what an agent should be able to see. Increasingly the real skill: a model with the approved spec, the review notes and the relevant code will beat a better model working from a paragraph.

House template

The fixed shape documents must follow in a workspace, enforced on submission. It is what stops agent output from being 1,400 words of fluent, unreviewable prose.