Arness Feature Extract

Extract a structured, prioritized feature backlog from all available project artifacts through guided conversation, aided by the arn-spark-product-strategist and arn-spark-ux-specialist agents (greenfield agents in this plugin) for feature analysis, prioritization, and UX flow analysis. This is a conversational skill that runs in normal conversation (NOT plan mode). The primary artifact is a feature backlog document that feeds into arn-code-feature-spec.

This skill bridges the greenfield pipeline into Arness's existing development pipeline. It takes all upstream artifacts -- product concept, architecture vision, spike results, style brief, static prototype validation (including showcase and debate reports), clickable prototype validation (including showcase, screen manifest, and debate reports), use cases (including postconditions, business rules, and debate reports), and visual grounding assets -- and distills them into a prioritized list of features with a local Feature Tracker for dependency management.

Each feature carries lean context (description, journey summary, UI behavior unique to the feature, validated components, use case references, debate insights, technical notes, acceptance criteria) with references to upstream UC documents. arn-code-feature-spec expands these references at spec time by reading the referenced UC documents directly.

Optionally, features can be uploaded as issues to the configured issue tracker (GitHub or Jira) for team visibility and tracking.

Prerequisites

At minimum, a product concept document should exist. Check in order:

1. Read the project's CLAUDE.md for a ## Arness section. If found, check the configured Vision directory for product-concept.md
2. If no ## Arness section found, check .arness/vision/product-concept.md at the project root

If a product concept is found: Read it as the primary source for feature extraction.

If no product concept is found: Ask the user: "No product concept found. I can extract features from your description of the product. What are the main things users should be able to do?"

Read the configured directories from the ## Arness section (use defaults if no config found):

• Use cases directory (default: .arness/use-cases)
• Prototypes directory (default: .arness/prototypes)
• Vision directory for the output (default: .arness/vision)
• Visual grounding directory (default: .arness/visual-grounding)

If no ## Arness section exists or Arness Spark fields are missing, inform the user: "Arness Spark is not configured for this project yet. Run /arn-brainstorming to get started — it will set everything up automatically." Do not proceed without it.

All references to use-cases/, prototypes/, and visual-grounding/ in this skill refer to the configured directories determined above.

Also check for and load (if available):

• [use-cases-dir]/README.md and [use-cases-dir]/UC-*.md -- for structured behavioral specs with actor goals, main success scenarios, alternate flows, business rules, and postconditions that map directly to features
• [use-cases-dir]/reviews/ -- for debate reports from arn-spark-use-cases-teams (consensus findings, business rule discovery, scope concerns, missing elements)
• architecture-vision.md (in Vision directory) -- for technical capabilities and platform features
• spike-results.md (in Vision directory) -- for validated/failed risks that affect feature scope, validated capabilities, and known limitations
• style-brief.md (in Vision directory) -- for UI patterns, visual tokens, and component style that imply features
• dev-setup.md (in Vision directory) -- for environment constraints that may affect feature scope
• [prototypes-dir]/static/final-report.md -- for validated visual components and their review scores
• [prototypes-dir]/static/v[N]/showcase/showcase-index.md -- for per-component visual captures with scores (scan for the latest version directory)
• [prototypes-dir]/static/v[N]/showcase-manifest.json -- for the component section list (maps library components to showcase sections)
• [prototypes-dir]/static/reviews/ -- for debate reports from arn-spark-static-prototype-teams (expert scoring, consensus, divergence on visual fidelity)
• [prototypes-dir]/clickable/final-report.md -- for validated user journeys, interaction test results, and journey screenshots
• [prototypes-dir]/clickable/v[N]/showcase/showcase-index.md -- for per-screen visual captures with journey mapping (scan for the latest version directory)
• [prototypes-dir]/clickable/v[N]/screen-manifest.json -- for the canonical screen list with routes and functional areas
• [prototypes-dir]/clickable/reviews/ -- for debate reports from arn-spark-clickable-prototype-teams (expert scoring, journey agreement, interaction quality debate)
• [prototypes-dir]/criteria.md -- for agreed validation criteria
• Prototype screens: scan [prototypes-dir]/clickable/ for versioned prototype app directories. Also check the project's screen/view directories (the location depends on the framework -- look at the project structure) -- each screen suggests features
• User journey definitions from the clickable prototype (journey templates and interaction reports in [prototypes-dir]/clickable/)
• [visual-grounding-dir]/references/ -- reference images (inspirational, inform visual target classification)
• [visual-grounding-dir]/designs/ -- design mockups (specification targets, inform visual target classification)
• [visual-grounding-dir]/brand/ -- brand assets (fixed constraints)

The output directory is the Vision directory determined above. If it does not exist, create it.

Workflow

Step 1: Load All Artifacts

Read all available project artifacts:

• Product concept: Core experience, interaction modes, trust model, platform requirements, scope boundaries, future considerations
• Architecture vision: Technology stack, system components, protocols, platform integration points
• Spike results: Validated and failed risks (failed risks may eliminate or alter features), validated capabilities and their limitations
• Style brief: UI patterns, visual tokens, and component customization that suggest features (settings panel implies settings feature, dark mode toggle implies theme feature, etc.). Also read the Component Style section for the library component inventory.
• Style brief Animation section (if present): Motion philosophy, animation approach, key patterns, timing characteristics — used to identify which features have animation requirements
• Static prototype results: Validated visual components, review scores, and the component showcase -- which UI elements are themed, validated, and ready to use
• Static prototype showcase: Per-component section captures from showcase-index.md and showcase-manifest.json -- the canonical list of validated library components with their showcase section numbers
• Clickable prototype results: Validated user journeys with step-by-step interaction evidence, journey screenshots showing how screens link together, and which interactions work
• Clickable prototype showcase: Per-screen captures from showcase-index.md and screen-manifest.json -- the canonical screen list with routes and functional areas, showing product-specific component compositions
• Debate reports (static prototype): Expert consensus, additions, and disagreements on visual fidelity from arn-spark-static-prototype-teams review files
• Debate reports (clickable prototype): Expert consensus, additions, and disagreements on interaction quality from arn-spark-clickable-prototype-teams review files, including journey assessment agreement
• Debate reports (use cases): Expert consensus, additions, and disagreements on behavioral specs from arn-spark-use-cases-teams review files, including missing use cases, missing actors, an