What Are Bolts?

A bolt is the atomic unit of construction in the DLC. It’s a well-scoped piece of work with clear boundaries, specific ARC constraint mappings, and testable acceptance criteria.

Why Bolts?

Traditional task decomposition (stories, tickets) often lacks:

• Direct traceability to architecture constraints
• Explicit acceptance criteria that map to testing
• Scope discipline — tasks grow unbounded

Bolts solve this by being:

• Scoped by constraint — Each bolt maps to specific ARC rules
• Independently verifiable — Acceptance criteria are testable without context
• Small enough to review — One bolt = one reviewable unit of work

Anatomy of a Bolt

Scope

What exactly this bolt builds — no more, no less. If the description includes “and also,” it’s probably two bolts.

ARC Constraint Mapping

Which ARC constraints this bolt must satisfy. During execution, each mapped constraint is checked. Example:

## ARC Constraints
- MUST-001: All API inputs validated against JSON Schema
- MUST-003: Return 200 for all valid email formats
- MUST-NOT-001: Do not reveal email existence

Acceptance Criteria

Specific, testable conditions for “done”:

## Acceptance Criteria
- [ ] Endpoint accepts POST with { "email": "..." }
- [ ] Returns 200 OK for valid email formats
- [ ] Returns 400 for invalid email formats
- [ ] Rate limiting enforced (3/hour/email)

Testing Requirements

What tests must exist and pass for this bolt to be complete.

Dependencies

Other bolts or artifacts that must exist first.

Bolt Sizing

Size	Characteristics	Example
Too small	One line of code, no meaningful constraint mapping	”Add import statement”
Right size	1 endpoint, 1 component, or 1 integration point with 2–5 constraints	”Create password reset endpoint with validation”
Too large	Multiple endpoints, multiple components, 6+ constraints	”Build entire password reset system”

A good bolt takes 30 minutes to 2 hours of focused implementation.

Bolt Lifecycle

graph LR
    A[Bolt Spec Written] --> B[Bolt Executed]
    B --> C[Code Reviewed]
    C --> D[Constraints Verified]

    style A fill:#E8F5E9
    style B fill:#FFF3E0
    style C fill:#E3F2FD
    style D fill:#F3E5F5

1. Written — Julian decomposes a Feature into bolt specs (cat-bolt-writer)
2. Executed — Marcus implements the bolt against ARC constraints (cat-bolt-execution)
3. Reviewed — Marcus and Vera review the code (cat-code-review)
4. Verified — ARC adherence check confirms constraint compliance

Bolts vs Tasks/Stories

Aspect	Bolt	Task/Story
Scope driver	ARC constraints	User requirements
Acceptance	Constraint compliance + criteria	Definition of done
Traceability	Direct to ARC → Intent Brief	Often informal
Review focus	ARC constraint verification	Feature completeness
Size	30 min – 2 hours	Varies widely

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See Also: Write Bolt Specs · Execute Bolts · Construction Phase