Add Amygdala habit learning feature to memento

[dpuglielli]

Summary

Add Amygdala as a feature within memento that extracts behavioral habits from session history and injects them as low-context reflexes. While memento handles declarative memory (what happened), amygdala handles procedural memory (how to behave).

Background

Analysis of 139 sessions across 2 projects revealed consistent behavioral patterns (85-100% frequency) that could be extracted as "habits" - low-token reflexes that reinforce good practices without the overhead of full mantra rules.

Design document: docs/plans/2026-01-17-amygdala-design.md

Phase 1: Manual Curation

Features

• Storage: ~/.claude/amygdala/habits.md (global) + .claude/amygdala/habits.md (project)
• Format: Ultra-compact stimulus→response (error|bug → reproduce → evidence → fix)
• Injection: Via memento's SessionStart hook with 🧠 emoji
• Skills:
  • /memento:amygdala - Show current habits
  • /memento:amygdala add "<verbose>" - Add habit with auto-compaction

Acceptance Criteria

• Habits appear in session context with 🧠 emoji
• /memento:amygdala shows current global and project habits
• /memento:amygdala add "verbose description" compacts to stimulus→response format
• /memento:amygdala add prompts for global vs project destination
• Global habits (~/.claude/amygdala/habits.md) work across all projects
• Project habits (.claude/amygdala/habits.md) are additive to global
• Total habit injection stays under ~100 tokens
• Tests cover habit loading and skill functionality

Files to Create/Modify

memento/
├── hooks/
│   └── session-start.js    # MODIFY: add habit loading
├── commands/
│   ├── amygdala.md         # NEW: show habits
│   └── amygdala-add.md     # NEW: add habit (verbose→compact)
├── lib/
│   └── amygdala.js         # NEW: habit loading utilities
└── __tests__/
    └── amygdala.test.js    # NEW: tests

Phase 2: Automatic Learning (Future)

• /memento:amygdala learn - Analyze sessions, suggest habits
• /memento:amygdala prune - Remove stale habits
• Confidence scoring and trend tracking

Related

• Exploration branch: chore/explore-amygdala
• Session file: .claude/sessions/chore-explore-amygdala.md

[dpuglielli]

Design Document Available

The exploration work is complete and the design document is now available:

Location: docs/plans/2026-01-17-amygdala-design.md

PR: #127

The design covers:

• Storage structure (global + project habits)
• Ultra-compact habit format (stimulus → response)
• Injection via memento's SessionStart hook
• Skills: /memento:amygdala, /memento:amygdala add
• Coexistence with mantra rules
• Implementation plan (Phase 1 ~3-4 hours)