Data Flow Review

Expert review pass for data-flow / state-ownership / lifetime / boundary topology -- the lens that asks "who creates this, who owns it, who consumes it, who decides about it" at every non-trivial entity in scope, and flags mismatches between conceptual scope and instantiation scope (singleton inside a per-note constructor), wrong direction of data flow (consumer reaches up into producer), constructors that reach out into the world, hidden state via module-mutable / closure capture, identity-vs-value confusion (Hickey), wrong dependency direction (domain depending on infrastructure), missing teardown on owned objects, and boundary placement that doesn't match the natural seams. The "draw the data-flow diagram before reading the body" discipline. Especially load-bearing in a world where the implementation body is increasingly AI-written and routinely regenerated -- the topology survives replacements; the body doesn't. Reviews the current branch diff against main by default, a specific file/PR with `/data-flow-review <path>` or `/data-flow-review <PR#>`, or a git range. Auto-delegates depth to the `data-flow` subagent. Produces severity-labeled findings with file:line references plus a data-flow diagram per finding when the alternative is concrete. Does NOT post comments.

mkdir -p ~/.claude/skills/data-flow-review
curl -L https://claudskills.com/skills/data-flow-review/SKILL.md \
  -o ~/.claude/skills/data-flow-review/SKILL.md

@misc{data-flow-review-2026,
  author    = {austintheriot},
  title     = {Data Flow Review [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/data-flow-review/}
}