Lisa CLAUDE.md

Lisa — Lisp-based Intelligent Software Agents

Forward-chaining expert system shell in Common Lisp (Rete algorithm, CLOS/MOP, certainty factors). Integrated with Claude via tool-use for natural-language medical diagnosis (MYCIN rulebase).

Build & Load

Requires SBCL with Quicklisp. From the SBCL REPL at project root:

;; Load Lisa core
(load "lisa.asd")
(asdf:load-system :lisa)

;; Load the MYCIN rules (classes + rules, no assertions)
(in-package :lisa-user)
(load "examples/mycin.lisp")

;; Load and start the LLM bridge
(asdf:load-system :lisa-bridge)
(lisa-bridge:start)  ; starts on port 8090

To stop: (lisa-bridge:stop)

Choosing a belief system

The bridge honors LISA_BELIEF_SYSTEM at startup. Dempster-Shafer is the default — it exposes ignorance intervals {bel, pl, ignorance} that the LLM can narrate meaningfully. Override with the env var:

LISA_BELIEF_SYSTEM=cf sbcl ...   # certainty factors (Shortliffe-Buchanan)
LISA_BELIEF_SYSTEM=ds sbcl ...   # Dempster-Shafer (default)

Per-session overrides ride on POST /reset with body {"belief_system": "cf" | "ds"}. /conclusions echoes the active system in its response and emits {bel, pl, ignorance} payloads under DS.

Project Structure

lisa.asd              — Core system definition (depends on log4cl)
lisa-bridge.asd       — Bridge system (depends on lisa, hunchentoot, jzon, bordeaux-threads)
src/
  core/               — Rete engine, rules, facts, conflict resolution
  belief-systems/     — Pluggable belief-system protocol
    protocol.lisp     — Generic function surface + dispatcher + use-system
    certainty-factors/— Shortliffe-Buchanan CF implementation
    dempster-shafer/  — Simplified [Bel, Pl] interval implementation
  rete/reference/     — Rete network nodes and compiler
  llm/bridge/         — HTTP bridge for LLM integration
    package.lisp      — :lisa-bridge package
    session.lisp      — Entity registry, session reset
    server.lisp       — Hunchentoot start/stop; LISA_BELIEF_SYSTEM env var
    handlers.lisp     — REST endpoints (belief-system-aware)
  llm/claude/         — Claude tool-use integration
    driver.py         — Python client: tool-call loop; transcript capture
    tools.json        — Tool schemas (assert_fact, run_inference, get_conclusions, etc.)
    system-prompt.md  — Clinical diagnostic system prompt (18 rules, CF/DS output)
examples/
  mycin.lisp          — MYCIN rules (18 rules incl. 3 disconfirming; culture-1, culture-1a, culture-2, culture-3)
bin/
  test-culture-1.sh   — End-to-end bridge test (curl-based)
  run-mycin.sh        — Same as test-culture-1.sh (legacy name)