pvf-extension

name: pvf-extension description: Add, edit, rename, or review pvf extension behavior. Use when changing Extension implementations, ExtensionHost composition, extension-owned state, input hooks, AppEvent handling, background drain, status bar segments, extension UI snapshots, or reload/reset behavior.

PVF Extension

Use this skill for changes centered on pvf feature extensions and their runtime state.

Start

Read only the relevant docs/reference.md Extensions section before changing extension contracts or host composition. Read only the relevant docs/reference.md Palette section when an extension exposes data to a palette or opens a palette. Read only the relevant docs/reference.md Rendering And Workers section when extension work can outlive one event-loop iteration. Read the relevant part of docs/architecture.md when extension ownership, event flow, worker flow, or subsystem boundaries change. Read the relevant section of docs/testing.md before placing new extension tests.

Implementation Checks

• Keep extension state owned by ExtensionHost unless the architecture changes deliberately.
• Preserve hook ordering and first-claim input behavior when adding input interception.
• Keep event observation driven by typed AppEvent values rather than ad hoc cross-module calls.
• Make background drain report whether visible or behavioral state changed.
• Expose palette-facing data through a small UI snapshot instead of leaking extension internals.
• Keep status-bar output optional and compact.
• If document reload affects the extension, define the reset, preserve, or rehydrate behavior explicitly.
• If the extension starts asynchronous work, define owner, shutdown path, cancellation model, stale-result identity, and event propagation.

Tests And Docs

• Add or update state tests for event handling, input hooks, background drain, status output, and reload/reset behavior.
• Add host tests when composition, ordering, snapshot data, or cross-extension interactions change.
• Update docs/reference.md for extension contract, host composition, built-in extension behavior, worker, cancellation, or stale-result contract changes.
• Update docs/architecture.md only when ownership, event flow, worker flow, or boundary rationale changes.