---
date: '2026-02-13T16:45:00Z'
author: claude-opus-4-6
session: session_01Uo5E7GhzPyeQPu5vyPymzw
type: handoff
importance: 0.5
tags: [handoff, design-system, fingerprint-colors, ws7]
supersedes: null
signature: pending
---

# Handoff: Agent Fingerprint Colors

## What Was Done This Session

- Implemented `deriveFingerprintColor` utility with full TDD (10 tests)
- Added RGB-to-HSL and HSL-to-RGB color space conversion helpers
- Added NaN guard for malformed fingerprint input
- Created `AgentColorSwatch` component (renders colored circle with optional raw-color ghost + hex label)
- Added optional `color` prop to `KeyFingerprint` (left-border accent highlight)
- Added "Agent Fingerprint Colors" demo section to design system showcase
- Exported `deriveFingerprintColor`, `FingerprintColor`, `AgentColorSwatch`, `AgentColorSwatchProps` from package barrels

## What's Not Done Yet

- No tests for `AgentColorSwatch` component (render tests) — plan only specified utility tests
- No tests for `KeyFingerprint` `color` prop
- Visual testing of demo section (typecheck passes, but no browser verification in this session)

## Current State

- Branch: `claude/agent-fingerprint-colors-5AUI5`
- Tests: 45 passing (33 agent-identity-params + 12 design-system), 0 failing
- Typecheck: clean
- Lint: clean
- 6 commits pushed to remote

## Decisions Made

- Added `|| 0` NaN guard to `parseInt` calls in `deriveFingerprintColor` — defensive measure against malformed fingerprints propagating NaN through color conversions
- Kept `rgbToHsl`, `hslToRgb`, `rgbToHex` as private (non-exported) helpers — they're implementation details of the fingerprint color algorithm, not general-purpose utilities
- Placed all color derivation code in `agent-identity-params.ts` (same file as identity ring derivation) rather than a new file — keeps all fingerprint/identity visual derivation co-located

## Open Questions

- Should `AgentColorSwatch` have render tests? The plan didn't include them, but the component has conditional rendering logic (raw vs hex comparison)
- Is the saturation/lightness clamping range (S: 30-100, L: 35-65) correct for the project's dark theme? Visual verification needed

## Where to Start Next

1. Run `pnpm --filter @moltnet/design-system demo` to visually verify the new section
2. Consider adding component render tests if coverage is a concern
3. This feature could be integrated into the landing page agent cards or Moltbook profiles
