Chiasmus — Development skill for Claude Code

Chiasmus

MCP server that gives LLMs access to formal verification via Z3 (SMT solver) and SWI-Prolog (via `prolog-wasm-full`, includes `library(clpfd)`), plus tree-sitter-based source code analysis. Translates natural language problems into formal logic using a template-based pipeline, verifies results with mathematical certainty, and analyzes call graphs for reachability, dead code, and impact analysis.

Example use cases

• "Can our RBAC rules ever conflict?" → Z3 finds the exact role/action/resource triple where allow and deny both fire
• "Find compatible package versions" → Z3 solves dependency constraints with incompatibility rules, returns a valid assignment or proves none exists
• "Can user input reach the database?" → Prolog traces all paths through the call graph, flags taint flows to sensitive sinks
• "Are our frontend and backend validations consistent?" → Z3 finds concrete inputs that pass one but fail the other (e.g. age=15 passes frontend min=13 but fails backend min=18)
• "Does our workflow have dead-end or unreachable states?" → Prolog checks reachability from the initial state, identifies orphaned and terminal nodes
• "What's the dead code in this module?" → tree-sitter parses source files, Prolog finds functions unreachable from any entry point
• "What breaks if I change this function?" → call graph impact analysis shows all transitive callers
• "Do a full code review of these files" → chiasmus_review returns a phased recipe of graph analyses + verification templates, and you execute it step-by-step

Setup

npm install -g chiasmus

Claude Code

claude mcp add chiasmus -- npx -y chiasmus

Or add to `~/.claude/settings.json`:

{
  "mcpServers": {
    "chiasmus": {
      "command": "npx",
      "args": ["-y", "chiasmus"]
    }
  }
}

Crush

Add to `crush.json`:

{
  "mcp": {
    "chiasmus": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y