DynamoDB Axioms

This document is a set of design axioms for DynamoDB applications. It is intended to be read by an agent with no other context about the application and used to produce a defensible data-layer design.

Resolving the skill's own paths

This skill is host-agnostic — it runs under Claude Code, Kiro, Codex, Cursor, a plain terminal, or CI. Where it lives on disk depends on the host (~/.claude/skills/…, ~/.kiro/…, ~/.codex/…, ~/.cursor/…, a repo checkout, anywhere). The agent's working directory is the user's project, not the skill bundle, so relative paths like scripts/calculate_costs.py will not resolve. Throughout this document, ${SKILL_DIR} means the absolute path of the directory that contains this SKILL.md file (the skill root, which holds scripts/ and references/).

Resolve ${SKILL_DIR} once per session, then reuse it. Pick the first method that works in your host:

1. You already know it. You loaded SKILL.md from a path — ${SKILL_DIR} is the directory that file is in. This is the most reliable source; prefer it.
2. An environment variable. If $DDB_SKILL_DIR is set, trust it.
3. The bundled resolver (host-neutral, no host assumptions). It searches the common install roots and verifies the hit against sentinel files, so it never returns the wrong directory silently: