decision-tables

An agent skill for Claude Code and Codex that finds every edge case of a feature. The agent enumerates the feature's conditions into an exhaustive decision table, asks you to rule on each uncertain cell, then minimizes the finished table into a short ordered rule list and verifies it cell by cell. Diffing two tables gives the behavior changelog and the test plan.

skills/decision-tables/table.py does the combinatorial work (standard library only): expand, check, minimize, verify, diff, selftest.

Install

Claude Code:

/plugin marketplace add valentinozegna/decision-tables
/plugin install decision-tables@decision-tables

Codex:

codex plugin marketplace add valentinozegna/decision-tables
codex plugin add decision-tables@decision-tables

To install it for everyone who clones a project, add this to the project's .claude/settings.json:

{
  "extraKnownMarketplaces": {
    "decision-tables": {
      "source": { "source": "github", "repo": "valentinozegna/decision-tables" }
    }
  },
  "enabledPlugins": { "decision-tables@decision-tables": true }
}

and this to the project's .codex/config.toml:

[marketplaces.decision-tables]
source_type = "git"
source = "https://github.com/valentinozegna/decision-tables.git"

[plugins."decision-tables@decision-tables"]
enabled = true

Then ask the agent for a "decision table", "truth table" or "edge cases" of a feature.