ux-heuristic-eval

Heuristic Evaluation Sub-Skill

Version: 1.0.0 Framework: Jerry User-Experience -- Heuristic Evaluation Constitutional Compliance: Jerry Constitution v1.0 Parent Skill: /user-experience (skills/user-experience/SKILL.md) Wave: 1 (Zero-Dependency) Project: PROJ-022 User Experience Skill | GitHub Issue #138

Document Sections

Section	Purpose
Document Audience	Triple-Lens audience guide
Purpose	Sub-skill overview and key capabilities
When to Use This Sub-Skill	Activation triggers and scope boundaries
Available Agents	Single agent with role, model, and output location
P-003 Compliance	Worker agent hierarchy position
Invoking the Agent	Invocation via ux-orchestrator
Methodology	Nielsen's 10 heuristics, severity scale, evaluation workflow, single-evaluator reliability
MCP Dependencies	Figma REQ with screenshot-input fallback; Context7 for UX docs
Output Specification	Output location, L0/L1/L2 structure, required sections
Routing	Keywords and lifecycle-stage routing integration
Cross-Framework Integration	Handoff to Behavior Design, HEART Metrics, and CRISIS mode
Synthesis Hypothesis Confidence	Confidence classifications for heuristic evaluation outputs
Constitutional Compliance	Governing principles
Registration	H-26(c) parent-routed registration model and AGENTS.md confirmation
Deployment Status	Wave 1 stub agent status and implementation timeline
Quick Reference	Common workflows and agent selection hints
References	Full repo-relative paths, requirements traceability, external citations

Document Audience (Triple-Lens)

This SKILL.md serves multiple audiences:

Level	Audience	Sections to Focus On
L0 (Stakeholder)	Product managers, designers	Purpose, When to Use This Sub-Skill, Quick Reference
L1 (Developer)	Engineers invoking the agent	Invoking the Agent, Methodology, Output Specification
L2 (Architect)	Workflow designers, skill maintainers	Cross-Framework Integration, MCP Dependencies, Synthesis Hypothesis Confidence

---

Purpose

The Heuristic Evaluation sub-skill provides structured, evidence-based usability evaluation using Nielsen's 10 usability heuristics. It targets tiny teams (1-5 people) who lack dedicated UX evaluators by providing AI-augmented systematic interface inspection with severity-rated findings and actionable remediation recommendations.

This sub-skill is part of Wave 1 (Zero-Dependency), meaning it requires no prior wave completions and operates with minimal infrastructure. It is the foundation evaluation framework that other sub-skills build upon.

Key Capabilities

• Systematic Heuristic Inspection -- Evaluates interfaces against all 10 of Nielsen's usability heuristics sequentially, ensuring complete coverage
• Severity-Rated Findings -- Each finding receives a 0-4 severity rating per Nielsen's severity taxonomy (Not a problem to Usability catastrophe) with evidence from the interface
• Remediation Recommendations -- Actionable fix suggestions with effort estimates (Low/Medium/High) for each finding
• Multi-Screen Evaluation -- Coordinates evaluation across multiple screens or flows with finding deduplication
• Model Escalation -- Default Haiku for high-volume checklist evaluation; auto-escalates to Sonnet for complex evaluations
• Cross-Framework Feed -- Findings feed directly into Behavior Design diagnosis and HEART Metrics measurement

Source: Key capabilities derived from parent SKILL.md [Key Capabilities] (line 103: "Heuristic Evaluation -- Nielsen's 10 Heuristics with severity-rated findings (Wave 1)") and [Available Agents] (lines 152, 165).

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When to Use This Sub-Skill

Activate when:

• Evaluating an existing interface against established usability principles
• Conducting a structured usability audit with severity-rated findings
• Reviewing interface design quality during the "During design" lifecycle stage
• Performing interface review as part of a comprehensive UX audit (multi-sub-skill route with HEART Metrics)
• Executing CRISIS mode step 1 (identify UX issues via Nielsen's 10 heuristics)
• Evaluating AI product interfaces as an interim path when the AI-First Design sub-skill is not yet deployed
• Needing a baseline usability assessment before deeper behavioral or metrics analysis

Do NOT use for:

• Diagnosing why users fail to take a specific action -- use /ux-behavior-design (Fogg B=MAP) instead. Heuristic evaluation identifies design-level issues but does not trace behavioral root causes.
• Measuring quantitative UX health metrics -- use /ux-heart-metrics (Google GSM) instead. Heuristic evaluation produces qualitative findings, not metric baselines.
• Accessibility-specific compliance auditing -- use /ux-inclusive-design (WCAG 2.2) instead. Heuristic evaluation covers general usability; dedicated accessibility evaluation requires WCAG success criteria.
• Testing hypotheses about design changes -- use /ux-lean-ux (Lean UX) instead. Heuristic evaluation assesses existing interfaces, not hypothesis-driven experiments.
• Security-focused interface review -- use /eng-team instead. Heuristic evaluation applies usability principles, not security threat models.
• General research without UX evaluation focus -- use /problem-solving instead.

Source: Routing logic derived from parent SKILL.md [Lifecycle-Stage Routing] (lines 295-334) and skills/user-experience/rules/ux-routing-rules.md [Stage Routing Table], [Common Intent Resolution].

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Available Agents

Agent	Role	Tier	Mode	Model	Output Location
ux-heuristic-evaluator**	Nielsen heuristic evaluation specialist	T4	Systematic	Haiku*	projects/${JERRY_PROJECT}/engagements/{engagement-id}/ux-heuristic-evaluator-{topic-slug}.md

*Haiku for high-volume checklist evaluation; escalates to Sonnet when: (1) critical finding count >= 3 (severity 3 or 4), (2) Figma MCP benchmark fails pre-launch threshold, or (3) evaluation spans > 50 screens. Escalation is automatic within the orchestrator's routing logic per AD-M-009 model selection justification.

**STUB: The agent definition file (skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md) currently contains frontmatter, identity, purpose, and guardrails sections only. Full agent body implementation (<input>, <capabilities>, <methodology>, <output> sections) is pending Wave 1 completion of PROJ-022 EPIC-002. The SKILL.md specifies the methodology and output contract that the agent will implement.

Tool tier: T4 (External) = Read, Write, Edit, Glob, Grep + WebSearch, WebFetch + Context7 MCP. The T4 tier enables access to external UX standards documentation via Context7 and web search. Bash is intentionally excluded; T4 tier does not require shell access for MCP operations. See agent-development-standards.md [Tool Security Tiers] for full tier definitions.

The agent produces output at three levels per AD-M-004:

• L0 (Executive Summary): Top 3-5 findings with severity ratings for stakeholders and cross-framework synthesis input.
• L1 (Technical Detail): Full evaluation of all 10 heuristics with per-finding evidence, severity rating, affected screens, and remediation recommendations.
• L2 (Strategic Implications): Cross-product usability patterns, organizational UX recommendations, and design evolution trajectory.

Source: Agent specification from parent SKILL.md [Available Agents] (line 152) and agent stub at skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md.

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P-003 Compliance

The /ux-heuristic-eval sub-skill contains a single worker agent. It is invoked by the ux-orchestrator (T5) via the Agent tool. The agent does NOT have Agent tool access and MUST NOT spawn sub-agents.

MAIN CONTEXT (user request)
    |
    v
ux-orchestrator (T5, Opus, Integrative) -- parent orchestrator
    |
    +-- ux-heuristic-evaluator (T4, Systematic, Haiku) -- THIS sub-skill's worker
    +-- [other sub-skill workers...]

Enforcement:

• disallowedTools: [Agent] declared in skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md frontmatter
• P-003 prohibition in skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.governance.yaml capabilities.forbidden_actions
• CI gate validates no sub-skill agent has Agent access (documented in skills/user-experience/rules/ci-checks.md)

Source: P-003 hierarchy from parent SKILL.md [P-003 Compliance] (lines 174-196).

---

Invoking the Agent

This is a sub-skill invoked by the ux-orchestrator, not directly by users. Users interact with the parent /user-experience skill, which routes to this sub-skill based on lifecycle-stage triage.

Via Natural Language (to parent skill)

"Evaluate this dashboard design against Nielsen's heuristics"
"Run a usability audit on the settings page"
"Check this interface for usability issues"

The ux-orchestrator routes these requests to ux-heuristic-evaluator based on the [Stage Routing Table] in skills/user-experience/rules/ux-routing-rules.md.

Via Explicit Agent Request (to parent skill)

"Use ux-heuristic-evaluator to audit the navigation patterns"
"Have ux-heuristic-evaluator evaluate the form design"

Via Agent Tool (orchestrator internal)

The ux-orchestrator invokes the agent via the Agent tool:

Agent(
    description="ux-heuristic-evaluator: Heuristic evaluation of settings page",
    subagent_type="jerry:ux-heuristic-evaluator",
    prompt="""
## UX CONTEXT (REQUIRED)
- **Engagement ID:** UX-0001
- **Topic:** Settings Page Heuristic Evaluation
- **Product:** [product name and domain]
- **Target Users:** [user description]
- **Input:** [screenshots, Figma link, or interface description]

## TASK
Perform a Nielsen heuristic evaluation of the settings page.
Evaluate all 10 heuristics. Rate severity 0-4 for each finding.
Produce ranked findings with remediation recommendations.

## MANDATORY PERSISTENCE (P-002)
Create file at: projects/${JERRY_PROJECT}/engagements/UX-0001/ux-heuristic-evaluator-settings-page.md
"""
)

Governance codification (AD-M-007): The session_context contract (on_receive/on_send) is specified in ux-heuristic-evaluator.governance.yaml per AD-M-007. The on_receive steps validate engagement ID, product context, and prior evaluation findings. The on_send steps include severity-rated findings, heuristic coverage summary, and remediation recommendations.

Source: Invocation pattern from parent SKILL.md [Invoking an Agent] (lines 200-250).

---

Methodology

Nielsen's 10 Usability Heuristics

The evaluation systematically applies each of Nielsen's 10 heuristics to every screen or flow under review. Each heuristic is evaluated independently to ensure complete coverage.

#	Heuristic	Description	Evaluation Focus
H1	Visibility of System Status	The system should keep users informed about what is going on through appropriate feedback within reasonable time	Loading indicators, progress bars, state changes, confirmation messages
H2	Match Between System and Real World	The system should speak the users' language with words, phrases, and concepts familiar to the user	Terminology, metaphors, information ordering, cultural conventions
H3	User Control and Freedom	Users often perform actions by mistake and need a clearly marked "emergency exit" to leave the unwanted state	Undo/redo, cancel actions, navigation back, escape routes
H4	Consistency and Standards	Users should not have to wonder whether different words, situations, or actions mean the same thing	Internal consistency, platform conventions, industry standards
H5	Error Prevention	Even better than good error messages is a careful design that prevents problems from occurring in the first place	Constraints, confirmations, defaults, input validation
H6	Recognition Rather Than Recall	Minimize the user's memory load by making objects, actions, and options visible	Visible options, contextual help, recognizable patterns
H7	Flexibility and Efficiency of Use	Accelerators may speed up interaction for expert users while remaining invisible to novice users	Shortcuts, customization, adaptive interfaces
H8	Aesthetic and Minimalist Design	Dialogues should not contain information that is irrelevant or rarely needed	Visual clutter, information hierarchy, content prioritization
H9	Help Users Recognize, Diagnose, and Recover from Errors	Error messages should be expressed in plain language, precisely indicate the problem, and constructively suggest a solution	Error message clarity, recovery guidance, actionable feedback
H10	Help and Documentation	It may be necessary to provide help and documentation, focused on the user's task, listing concrete steps	Contextual help, documentation accessibility, task-oriented guidance

Source: Jakob Nielsen, "10 Usability Heuristics for User Interface Design" (1994, revised 2020). Nielsen Norman Group. Referenced in agent stub skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md [identity/expertise] and parent SKILL.md [Key Capabilities] (line 103).

Severity Rating Scale

Each finding receives a severity rating on the 0-4 scale. Severity determines remediation priority and influences cross-framework handoff decisions.

Severity	Name	Definition	Remediation Priority
0	Not a usability problem	No usability impact identified; does not need to be fixed	No action required
1	Cosmetic problem only	Cosmetic issue that need not be fixed unless extra time is available	Fix only if extra time is available
2	Minor usability problem	Users experience minor difficulty; low-priority fix	Low priority; fix in future release
3	Major usability problem	Significant usability problem; important to fix, high priority	High priority; important to fix
4	Usability catastrophe	Imperative to fix before product release; prevents task completion	Must fix before release

Cross-framework threshold: Findings with severity >= 2 (Minor usability problem or higher) are included in handoffs to downstream sub-skills (Behavior Design, HEART Metrics). Findings with severity 0-1 (Not a problem, Cosmetic only) are included in the full report but not propagated to cross-framework handoffs unless specifically requested.

Source: Severity scale from Jakob Nielsen, "Severity Ratings for Usability Problems" (1994). Referenced in agent governance file skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.governance.yaml [output_filtering: all_findings_must_have_severity_rating] and parent SKILL.md [Available Agents] footnote (line 165: "severity-rated findings").

Evaluation Workflow

The evaluation follows a 5-step systematic workflow.

Step	Name	Input	Output	Validation
1	Input Collection	Interface screenshots, Figma reference, or text description	Organized screen/flow inventory with input modality noted	At least one interface artifact provided; degraded mode disclosed if no Figma
2	Systematic Evaluation	Screen inventory + 10 heuristics checklist	Per-heuristic findings for each screen	All 10 heuristics evaluated for each screen; no heuristic skipped
3	Severity Rating	Raw findings	Severity-rated findings (0-4) with evidence	Every finding has a severity rating and specific interface evidence
4	Deduplication and Ranking	All severity-rated findings across screens	Deduplicated, ranked findings list	Duplicate findings across screens consolidated; ranked by severity descending
5	Report Generation	Ranked findings	L0/L1/L2 output artifact	Persisted to output location per P-002; all required sections present

Evaluation scope (Step 2): The evaluator operates in one of two modes depending on the request:

• Screen-level evaluation: Individual screen assessed against all 10 heuristics. Use for detailed single-screen audits. A "screen" is any distinct view, state, or flow step that presents a unique interface to the user (e.g., a 5-step checkout wizard counts as 5 screens; a modal dialog counts as a separate screen from its parent view).
• Flow-level evaluation: Multi-screen user journey evaluated for heuristic violations across transitions. Use for task-completion analysis where cross-screen consistency and navigation continuity matter.
• Default: Screen-level for requests mentioning specific screens; flow-level for requests mentioning user tasks or journeys.

Per-screen evaluation pattern: For each screen or flow, the evaluator applies all 10 heuristics sequentially (H1 through H10). This systematic approach prevents the common evaluation bias of focusing only on obvious problems while missing less salient but equally important heuristic violations.

AI-interaction heuristic supplement: When the orchestrator routes to this sub-skill for AI product evaluation (lifecycle stage "During design: Building AI product" with AI-First Design enabler not completed), the evaluator supplements Nielsen's 10 with three additional AI interaction heuristics: (a) Transparency -- is the AI's decision-making process visible to the user? (b) Controllability -- can the user override, correct, or guide the AI? (c) Error Recovery -- can the user recover when the AI produces incorrect output? These supplementary heuristics are marked as [AI-SUPPLEMENT] in the findings to distinguish them from Nielsen's core 10.

Source: AI-interaction supplement from parent SKILL.md [Lifecycle-Stage Routing] (line 312-313: "PAIR (interim)" defined as heuristic evaluation with AI-specific supplementary heuristics). Detailed routing logic in skills/user-experience/rules/ux-routing-rules.md [Stage Routing Table] "During design: Building AI product" row.

Single-Evaluator Reliability Note

Nielsen's heuristic evaluation methodology recommends 3-5 independent evaluators for reliable usability problem detection. Research shows that individual evaluators typically find only 35% of usability problems, with the aggregate across 3-5 evaluators reaching 75-80% coverage (Nielsen, 1994c).

This sub-skill operates with a single AI evaluator. The AI evaluator compensates for the single-evaluator limitation through systematic heuristic coverage: it applies all 10 heuristics sequentially to every screen, eliminating the heuristic omission bias that human evaluators commonly exhibit (where individual evaluators unconsciously focus on a subset of heuristics aligned with their expertise). This systematic approach ensures no heuristic is skipped, which is the primary source of coverage loss in single-human-evaluator assessments.

Acknowledged limitation (P-022): A single AI evaluator cannot replicate the perspective diversity that multiple human evaluators provide. Context-specific usability issues -- those requiring domain expertise, cultural familiarity, or embodied interaction experience -- may be missed by AI evaluation alone. The AI evaluator may also exhibit systematic blind spots (e.g., overweighting visual design heuristics when evaluating from screenshots vs. underweighting interaction flow heuristics that require hands-on use).

Recommendation for high-stakes evaluations: For findings rated severity 3 (Major usability problem) or severity 4 (Usability catastrophe), supplement the AI evaluation with at least one human evaluator review before making major design decisions. This is especially important when: (a) the product serves specialized user populations, (b) findings will drive significant engineering investment, or (c) the evaluation was conducted in screenshot-input degraded mode without interactive observation.

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MCP Dependencies

Dependency Matrix

MCP Tool	Classification	Purpose	Fallback
Figma	REQ	Inspect design layers, component states, responsive behavior, style tokens	Screenshot-input mode: user provides design screenshots as image inputs
Storybook	ENH	Browse live component stories for evaluation context	Manual component inventory: user provides component list and documentation links
Context7	Available (current infrastructure)	Resolve and query UX framework documentation (Nielsen Norman Group, WCAG references)	WebSearch fallback per MCP-001 (mcp-tool-standards.md [Error Handling])

Figma Fallback: Screenshot-Input Mode

When the Figma MCP adapter is unavailable (current state -- adapter implementation is post-PROJ-022 scope), the evaluator operates in screenshot-input mode:

• Users provide design screenshots as image inputs or paste text descriptions of the interface
• The evaluation methodology remains identical; only the input modality changes
• Limitations in screenshot-input mode:
  • Cannot inspect component states (hover, focus, active, disabled)
  • Cannot verify responsive behavior across breakpoints
  • Cannot access style tokens or design system variables programmatically
• Output carries a degraded mode disclosure per P-022:

  [DEGRADED MODE] This evaluation was produced without Figma MCP access.
  Input was provided via screenshot-input mode. Some features are reduced:
  - Cannot inspect component states (hover, focus, active, disabled)
  - Cannot verify responsive behavior across breakpoints
  - Cannot access style tokens or design system variables programmatically
  

Context7 Usage

Per MCP-001 (.context/rules/mcp-tool-standards.md [Context7 Integration]), Context7 is used when the evaluation references external UX frameworks or standards by name:

Library/Framework	Usage
Nielsen Norman Group	Heuristic definitions, severity scale reference, evaluation methodology
WCAG 2.2	Accessibility-adjacent heuristic evaluation (H10: Help and Documentation)
Material Design / platform guidelines	H4: Consistency and Standards -- platform convention references

Protocol: call mcp__context7__resolve-library-id with the framework name, then mcp__context7__query-docs with the resolved ID and specific query. If Context7 returns no results, fall back to WebSearch per mcp-tool-standards.md [Error Handling].

Source: MCP dependency matrix from parent SKILL.md [MCP Integration Architecture] (line 402: /ux-heuristic-eval row) and skills/user-experience/rules/mcp-coordination.md [MCP Dependency Matrix], [Figma Dependency Risk Profile].

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Output Specification

Output Location

projects/${JERRY_PROJECT}/engagements/{engagement-id}/ux-heuristic-evaluator-{topic-slug}.md

Where:

• {engagement-id} follows the pattern UX-{NNNN} (e.g., UX-0001)
• {topic-slug} is a kebab-case descriptor of the evaluated interface (e.g., settings-page, checkout-flow)

Required Output Sections

Section	Level	Content
Executive Summary	L0	Top 3-5 findings by severity; overall usability assessment; heuristic coverage confirmation
Evaluation Context	L1	Product description, target users, screens evaluated, input modality (Figma/screenshot/text), MCP status
Findings by Heuristic	L1	Per-heuristic findings with: finding ID, heuristic violated, severity (0-4), affected screen/flow, evidence description, remediation recommendation, effort estimate (Low/Medium/High)
Ranked Findings Summary	L1	All findings ranked by severity (descending), deduplicated across screens
Remediation Roadmap	L1	Findings grouped by effort level with suggested implementation order
Strategic Implications	L2	Cross-product usability patterns, organizational UX maturity observations, design evolution recommendations
Synthesis Judgments Summary	L1	Each AI judgment call listed for synthesis confidence gate compliance
Handoff Data	L1	Structured data for downstream sub-skills: finding IDs, heuristic references, severity ratings, affected screens (for Behavior Design and HEART Metrics consumption)

Finding Format

Each finding follows a consistent structure:

### Finding F-{NNN}: {brief description}

- **Heuristic:** H{N} -- {heuristic name}
- **Severity:** {0-4} ({Nielsen severity name})
- **Screen/Flow:** {affected screen or user flow}
- **Evidence:** {specific interface observation that demonstrates the violation}
- **Remediation:** {actionable fix recommendation}
- **Effort:** {Low | Medium | High}

Source: Output location from parent SKILL.md [Available Agents] (line 152) and governance file skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.governance.yaml [output.location].

---

Routing

Trigger Keywords

Keyword	Routing Context
heuristic evaluation	Direct match -- primary trigger
usability audit	Direct match
Nielsen heuristics	Direct match
interface review	Direct match
severity rating	In combination with UX/usability context
usability inspection	Direct match
UX evaluation	Direct match; may also trigger parent skill

Lifecycle-Stage Routing Integration

This sub-skill is routed to by the ux-orchestrator in the following lifecycle-stage scenarios:

Stage	User Intent	Route Condition
During design	"Iterating on existing design"	Qualification: "Evaluating existing interface" (vs. "Testing hypotheses" which routes to /ux-lean-ux)
During design	"Building AI product"	When AI-First Design enabler is NOT completed or WSM < 7.80; supplements with AI-interaction heuristics
Any stage	"Comprehensive UX audit"	First sub-skill in multi-sub-skill route: /ux-heuristic-eval then /ux-heart-metrics
CRISIS	"Urgent UX problems"	Step 1 of fixed 3-skill CRISIS sequence

Wave Gating

This sub-skill is in Wave 1 (Zero-Dependency). It requires only KICKOFF-SIGNOFF.md completion for deployment. No prior wave sub-skills need to be completed.

Source: Routing integration from skills/user-experience/rules/ux-routing-rules.md [Stage Routing Table] and parent SKILL.md [Lifecycle-Stage Routing] (lines 295-334). Wave assignment from parent SKILL.md [Wave Architecture] (line 263).

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Cross-Framework Integration

Downstream Handoffs

This sub-skill produces findings that feed into other sub-skills via the Jerry handoff protocol (docs/schemas/handoff-v2.schema.json).

To Sub-Skill	Handoff Artifact	Key Fields	Trigger
/ux-behavior-design	Severity-rated findings	Finding ID, heuristic violated, severity (0-4), affected screen/flow	CRISIS mode step 1 to step 2; or explicit multi-sub-skill route
/ux-heart-metrics	Severity-rated findings with metric candidates	Finding ID, heuristic violated, severity (0-4), affected screen/flow, candidate HEART metric category (Happiness/Engagement/Adoption/Retention/Task success)	Comprehensive UX audit route; or CRISIS mode step 1 to step 3 (via step 2)

Handoff threshold: Only findings with severity >= 2 (Minor usability problem, Major usability problem, Usability catastrophe) are included in cross-framework handoffs. Severity 0-1 findings remain in the evaluation report but are not propagated downstream.

Upstream Inputs

This sub-skill may receive context from other sub-skills when invoked as part of a multi-sub-skill workflow:

From Sub-Skill	Context Provided	Usage
/ux-jtbd	Job statements and user motivations	Informs evaluation of H2 (Match Between System and Real World) and H7 (Flexibility and Efficiency)
/ux-atomic-design	Component inventory	Informs evaluation of H4 (Consistency and Standards) across components

CRISIS Mode Role

In CRISIS mode (evaluate-diagnose-measure sequence), this sub-skill executes as Step 1: Evaluate. It produces an objective severity-rated inventory of UX problems that the subsequent sub-skills consume:

1. This sub-skill (Step 1): Identify UX issues via Nielsen's 10 heuristics -- produces severity-rated findings
2. /ux-behavior-design (Step 2): Diagnose behavioral root causes via Fogg B=MAP -- receives findings with severity >= 2
3. /ux-heart-metrics (Step 3): Quantify impact using HEART Goals-Signals-Metrics -- establishes metric baselines

Source: Handoff data contracts from skills/user-experience/rules/ux-routing-rules.md [Handoff Data Contracts] and parent SKILL.md [Cross-Sub-Skill Handoff Data] (lines 474-487). CRISIS sequence from parent SKILL.md [Canonical Multi-Skill Workflow Sequences] (line 470) and skills/user-experience/rules/ux-routing-rules.md [CRISIS Routing].

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Synthesis Hypothesis Confidence

Heuristic evaluation outputs include synthesis hypotheses that carry confidence classifications per the synthesis validation protocol.

Synthesis Step	Typical Confidence	Rationale
Severity rating calibration across heuristics	MEDIUM	Severity ratings involve subjective judgment; calibration across Nielsen's 10 heuristics requires consistent application context
Comparative evaluation synthesis (cross-product or cross-version)	HIGH	Based on systematic checklist methodology with observable UI artifacts; HIGH when screenshots or screen recordings available as concrete evidence

Gate enforcement:

• HIGH outputs: Include a "Synthesis Judgments Summary" listing each AI judgment call. Acknowledgment required before design recommendations are generated.
• MEDIUM outputs: Include a "Validation Required" section. Design recommendations are withheld until validation against real user data or expert review is provided.

Source: Confidence classifications from skills/user-experience/rules/synthesis-validation.md [Sub-Skill Synthesis Output Map] (lines 58-59: /ux-heuristic-eval rows). Gate enforcement from parent SKILL.md [Synthesis Hypothesis Validation] (lines 338-372).

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Constitutional Compliance

All agents in this sub-skill adhere to the Jerry Constitution v1.0:

Principle	Requirement	Consequence of Violation
P-003	NEVER spawn recursive subagents -- worker agent, no Agent tool access	Agent hierarchy violation; uncontrolled token consumption
P-020	NEVER override user decisions on finding priority or remediation approach	Unauthorized action; trust erosion
P-022	NEVER inflate severity ratings without specific evidence from the interface	Governance undermined; quality assessment invalidated
P-001	NEVER present findings without evidence from the interface under review	Unreliable outputs; unfounded claims propagate downstream
P-002	NEVER leave evaluation output in transient context only -- persist to files	Context rot vulnerability; artifacts lost on session compaction

Per-agent enforcement: The ux-heuristic-evaluator agent declares:

• constitution.principles_applied: P-003, P-020, P-022, P-001, P-002 in skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.governance.yaml
• capabilities.forbidden_actions: 3 entries in NPT-009 format referencing the constitutional triplet
• disallowedTools: [Agent] in skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md frontmatter

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Registration

This sub-skill follows a parent-routed registration model. Sub-skills are not independently registered in CLAUDE.md or mandatory-skill-usage.md because they are routed through the parent /user-experience orchestrator (ux-orchestrator). This is an explicit H-26(c) exception for sub-skills: parent skills own the CLAUDE.md and mandatory-skill-usage.md registration; sub-skills are discovered and dispatched by the parent orchestrator's internal routing logic.

Registration Point	Status	Detail
CLAUDE.md skill table	Registered via parent	/user-experience is registered in CLAUDE.md; sub-skills are not independently listed
mandatory-skill-usage.md trigger map	Routed via parent	The /user-experience trigger map row includes "heuristic evaluation" as a positive keyword (H-22); requests matching this keyword route to the parent skill, which dispatches to this sub-skill
AGENTS.md agent registry	Registered	ux-heuristic-evaluator is listed in AGENTS.md under the User-Experience Skill Agents section
Parent SKILL.md agent table	Registered	ux-heuristic-evaluator is listed in skills/user-experience/SKILL.md [Available Agents]

H-26(c) exception rationale: Independent registration of sub-skills would create duplicate trigger map entries and ambiguous routing (AP-02 Bag of Triggers). The parent orchestrator owns lifecycle-stage routing logic and dispatches to the correct sub-skill based on triage qualification, not keyword matching alone. Sub-skill agents are registered in AGENTS.md for discoverability but routing flows through the parent.

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Deployment Status

Wave 1 Sub-Skill -- Stub Agent. This sub-skill is part of Wave 1 (Zero-Dependency) of PROJ-022. The companion agent file (skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md) is currently a stub -- it contains frontmatter, identity, purpose, and guardrails sections but lacks full <input>, <capabilities>, <methodology>, and <output> sections. Full agent implementation is pending Wave 1 completion of PROJ-022 EPIC-002. The SKILL.md itself is complete and specifies the methodology, output format, and routing integration that the agent will implement.

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Quick Reference

Common Workflows

Need	Command Example
Evaluate a specific page	"Evaluate this settings page against Nielsen's 10 heuristics"
Full interface audit	"Run a heuristic evaluation across all screens of the checkout flow"
Severity assessment	"What are the most severe usability issues in this dashboard?"
AI interface evaluation	"Evaluate this AI assistant interface for usability"
CRISIS triage (step 1)	"CRISIS: users are abandoning checkout -- urgent UX triage"
Comprehensive audit	"Full UX audit of the onboarding experience" (routes to heuristic eval + HEART metrics)

Agent Selection Hints

Keywords	Routes To
heuristic, usability, Nielsen, severity, inspection, evaluation, interface review	ux-heuristic-evaluator
behavior, Fogg, B=MAP, motivation, ability, prompt, trigger	/ux-behavior-design (not this sub-skill)
HEART, metrics, measurement, GSM, happiness, engagement	/ux-heart-metrics (not this sub-skill)
accessibility, WCAG, ARIA, screen reader, contrast	/ux-inclusive-design (not this sub-skill)

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References

Source	Content	Path
Parent SKILL.md	Sub-skill scope, wave architecture, routing, MCP dependencies, synthesis protocol	skills/user-experience/SKILL.md
Agent definition	Agent frontmatter, identity, expertise, guardrails	skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.md
Agent governance	Tool tier, forbidden actions, output validation, constitutional compliance	skills/ux-heuristic-eval/agents/ux-heuristic-evaluator.governance.yaml
UX routing rules	Lifecycle-stage routing, CRISIS sequence, handoff data contracts	skills/user-experience/rules/ux-routing-rules.md
MCP coordination	Figma REQ dependency, degraded mode behavior, Context7 usage	skills/user-experience/rules/mcp-coordination.md
Synthesis validation	Confidence gate protocol, per-sub-skill confidence map	skills/user-experience/rules/synthesis-validation.md
Wave progression	Wave 1 entry criteria, signoff requirements	skills/user-experience/rules/wave-progression.md
CI checks	P-003 enforcement, sub-skill validation gates	skills/user-experience/rules/ci-checks.md
Skill standards	H-25/H-26 skill structure requirements	.context/rules/skill-standards.md
Agent development standards	H-34 dual-file architecture, tool tiers, handoff protocol	.context/rules/agent-development-standards.md
Quality enforcement	Quality gate thresholds, criticality levels, strategy catalog	.context/rules/quality-enforcement.md
Handoff schema	Canonical handoff schema v2	docs/schemas/handoff-v2.schema.json
Agent governance schema	Governance YAML validation schema	docs/schemas/agent-governance-v1.schema.json

Requirements Traceability

Source	Content	Path
PROJ-022 PLAN.md	Project plan: sub-skill scope, wave assignment, acceptance criteria, implementation phases	projects/PROJ-022-user-experience-skill/PLAN.md
EPIC-002 (Wave 1 Deployment)	Parent work item for Wave 1 sub-skill implementation including this sub-skill	PROJ-022 EPIC-002 in projects/PROJ-022-user-experience-skill/WORKTRACKER.md
ORCHESTRATION.yaml	Orchestration plan governing the build sequence for this sub-skill	projects/PROJ-022-user-experience-skill/orchestration/ux-skill-build-20260303-001/ORCHESTRATION.yaml

External References

Source	Citation
Nielsen, J. (1994a)	"10 Usability Heuristics for User Interface Design." Nielsen Norman Group.
Nielsen, J. (1994b)	"Severity Ratings for Usability Problems." Nielsen Norman Group.
Nielsen, J. (1994c)	"How to Conduct a Heuristic Evaluation." Nielsen Norman Group.
Nielsen, J. (2020)	"10 Usability Heuristics for User Interface Design" (revised). Nielsen Norman Group.

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Sub-Skill Version: 1.0.0 Parent Skill: /user-experience v1.0.0 Constitutional Compliance: Jerry Constitution v1.0 Wave: 1 (Zero-Dependency) SSOT: skills/user-experience/SKILL.md Project: PROJ-022 User Experience Skill Created: 2026-03-04