# Spec-Driven Development with AI Agents

> Write the spec, let the agent implement against it — the SDD workflow (spec → plan → tasks → implement), when it beats prompt-and-iterate, and the tooling.

Spec-driven development inverts vibe coding: instead of steering an agent with corrective prompts, you invest in a written specification — requirements, constraints, acceptance criteria — and the agent implements against it, typically through a spec → plan → tasks → implement pipeline. It pays on substantial features and team settings; it's overhead for true exploration.

The second generation of agentic-coding wisdom is converging on something almost embarrassingly traditional: **write down what you want before building it.** Spec-driven development (SDD) is that discipline rebuilt for agents — where the spec isn't bureaucracy, it's the *program you write in English*, and the agent is its compiler.

## The inversion

[Vibe coding](/guides/prompting/vibe-coding-guide) steers downstream: prompt, inspect behavior, correct, repeat — every correction spent *after* implementation exists. SDD moves the steering upstream, where it's cheap. The workflow that emerged as canonical — popularized by GitHub's [Spec Kit](/tools/spec-kit) — runs in reviewed stages:

1. **Specify.** Author the spec: the problem, requirements, constraints, *acceptance criteria*. This is the thinking; expect it to be the hard part.
2. **Plan.** The agent derives a technical plan — architecture, components, trade-offs — and you review *that*, killing wrong directions while they're still paragraphs.
3. **Tasks.** The plan decomposes into discrete tasks with checkable outcomes — each sized for a focused session, each independently verifiable.
4. **Implement.** Agents execute tasks against the spec, with tests embodying the acceptance criteria. Review arrives as small, purposeful diffs traceable to requirements.

Each stage gate is the same trick: **review text before code, small before large.** A flawed assumption caught in the plan costs a sentence; caught in the diff, a day.

## Why agents specifically reward this

- **Context is fragile; files aren't.** Sessions compact, reset, and end — a spec on disk re-anchors any session, any agent, any teammate. It's the antidote to "the agent forgot what we agreed" ([the memory mechanics](/guides/configuration/claude-code-memory-context)).
- **Parallelism needs contracts.** Fan tasks out to [parallel sessions](/guides/advanced/parallel-claude-code-worktrees) or multiple agents and the spec is what keeps their outputs composable — shared intent, explicit interfaces.
- **Acceptance criteria become tests.** The spec's "done means…" lines translate directly into the verification that makes accepting agent code safe.
- **The artifact outlives the change.** Six months later, "why does it behave this way?" has a written answer. Vibe coding leaves behavior; SDD leaves *intent*.

## When to spec — and when not to

SDD earns its overhead on **work that outlives the session**: features with real surface area, integrations with contracts, team codebases, anything multiple agents will touch. It's the wrong tool for **exploration** — spikes, prototypes, "what would this feel like" — where the honest spec doesn't exist yet and writing one is fiction. The mature loop uses both: *vibe to discover, spec to build.* Prototype freely; when the throwaway proves the idea, write the spec the prototype taught you, and let agents build the real one against it.

> [!TIP]
> Already inside Claude Code, the lightweight on-ramp is built in: [plan mode](/guides/configuration/claude-code-settings-permissions) plus the [plan-feature](/commands/plan/plan-feature) and [breakdown-task](/commands/plan/breakdown-task) commands give you spec→plan→tasks ergonomics for medium work without adopting a full toolkit; [Spec Kit](/tools/spec-kit) adds the standardized pipeline and constitution when the team wants the whole discipline.

The deeper point survives any particular tool: as implementation gets cheaper, **specification becomes the engineering**. The teams getting the most from agents in 2026 aren't the best prompters — they're the best at saying precisely what they want and proving they got it.

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_Source: https://agentscamp.com/guides/workflow/spec-driven-development — Guide on AgentsCamp._