ASDLC

Agent-Spec-Driven Lifecycle

What is ASDLC?

• A development methodology where specs drive every decision
• Designed for human-agent collaboration, not just human teams
• Specs are living documents — blueprint + contract in one artifact
• Agents read specs before writing code, just like engineers should
• Eliminates ambiguity that causes LLM drift and hallucination

The Workflow

Each phase has a clear input and output. The spec is both the starting point and the acceptance gate.

Spec as Contract

# feature-name.spec.md

## Blueprint
- Architecture decisions and constraints
- API surface and data flow
- Anti-patterns to avoid

## Contract
- Definition of Done checklist
- Regression guardrails

### Scenarios
Given a valid slide container
When the user presses ArrowRight
Then the next slide becomes active
And the live region announces the change

Benefits

• Deterministic agent output — specs constrain what gets built
• Auditable decisions — every choice traces to a spec section
• Testable by default — Gherkin scenarios map directly to tests
• Human-agent handoff — either party can pick up from the spec
• Drift protection — verify phase catches spec-code divergence

Specs are the source of truth.

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