Implementation Spikes

This directory holds Cairn's implementation spikes — the build-prep tasks that take the decided architecture (the numbered spec §1–§11 and the Decision log) and exercise it against reality, on real hardware and real links.

A spike is not architecture and not a decision. It is a concrete, runnable task with explicit pass/fail thresholds that validates a bet the spec is making. Its results feed back into the spec: a passing spike ratifies a default into an ADR; a failing spike sends a question back to the design.

Why a separate area

The spec stays a clean statement of what Cairn is; the ADR log stays a clean statement of why. A spike record is a third thing — what we tried, on what, and what we learned. Keeping it out of both preserves the §3.13 discipline that the architecture documents describe a settled design, not a lab notebook.

Index

Spike	Title	Status	Validates
0001	Walking skeleton, WAN-sync, and Pi cost	Proposed	ADR-0001 projection cost · §6.2 convergence under real partition · ADR-0013 availability floor · day-one serialization/signature/digest primitives