Nielsen Heuristic Assessment

The design should always keep users informed about what is going on, through appropriate feedback within a reasonable amount of time.

This is the foundational commitment of the entire design system. Nodus exists to make algorithmic structure visible. Every pattern in the system is, in some way, an answer to this heuristic.

The design should speak the users' language. Use words, phrases, and concepts familiar to the user, rather than internal jargon. Follow real-world conventions.

The Nodus patterns use physical metaphors — membrane, witness, chorus, ledger, fence — to ground abstract AI concepts in tangible experience. But protocol-level patterns introduce specialist vocabulary that may not serve broader adoption.

Users often perform actions by mistake. They need a clearly marked emergency exit to leave unwanted actions without an extended process. Support undo and redo.

The human-in-the-loop pattern family (21–26) is built entirely around this heuristic. ConsentFlow is revocable. CeremonyGate has an undo period. CorrectionFlow enables override. The system treats human authority as non-negotiable.

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform and industry conventions.

The three-layer token architecture (primitive → semantic → component) is the consistency engine. The new status, risk, confidence, opacity, and tracking token families extend this foundation to cover the full pattern vocabulary.

Good error messages are important, but the best designs carefully prevent problems from occurring in the first place. Eliminate error-prone conditions or present confirmation options.

CeremonyGate is the purest expression of error prevention — multi-step confirmation with enforced delays and typed confirmation phrases. GuardrailIndicator shows active safety constraints before errors occur. But the system lacks input-level prevention patterns.

Minimize the user's memory load by making elements, actions, and options visible. Users shouldn't have to remember information from one part of the interface to another.

The provenance and citation patterns are explicitly designed to eliminate recall — every claim has an inline source, every datum has a traceable origin, every agent action is logged with full context. The system makes memory external.

Shortcuts — hidden from novice users — may speed up the interaction for the expert user. Allow customization so users can tailor frequent actions.

This is the system's weakest heuristic. The patterns are designed for inspection and transparency — making everything visible — but provide few mechanisms for power users to move faster. The philosophy prioritizes legibility over speed, which creates tension with this heuristic.

Interfaces should not contain information that is irrelevant or rarely needed. Every extra unit of information competes with relevant units and diminishes their visibility.

The Bauhaus foundation IS this heuristic. Zero border radius, three colors, two typefaces, exposed structure as decoration. The philosophy manifesto articulates this as the core aesthetic commitment. Every element must earn its place.

Error messages should be in plain language, precisely indicate the problem, and constructively suggest a solution.

The EscalationBanner is the best expression — the agent recognizes its own limits and tells the user exactly what went wrong and what to do. RetryLedger shows the full error→recovery arc. But lower-level error states show raw technical strings without guidance.

It's best if the system doesn't need additional explanation. However, it may be necessary to provide documentation to help users understand how to complete their tasks.

The system is self-documenting in the sense that every datum has provenance, every agent has a card, every action has a timeline entry. But there is no contextual help layer — no tooltips, no onboarding flow, no 'what does this mean' pattern for the patterns themselves.