py-shiny

Use when observing server-side state of a Shiny for Python (py-shiny) app - inspecting reactive/calc values in a running session, capturing current input/output state, exposing internal values to a test harness, asserting server-side values in snapshot tests, or when tempted to add print statements or hidden outputs to see server-side values. (For writing Playwright end-to-end tests against the rendered UI, use the testing skill.)

Use when writing or running end-to-end tests for a Shiny for Python (py-shiny) app - launching an app under pytest, locating and asserting on UI components (inputs, outputs, cards, navsets), simulating user interaction with Playwright, or when tempted to hand-roll CSS selectors, raw Playwright locators, or sleep() waits against Shiny-rendered HTML.

Use when adding observability to a Shiny for Python (py-shiny) app with OpenTelemetry - tracing reactive execution, profiling slow outputs or update cycles, monitoring sessions in production, exporting spans to a backend (Jaeger, Logfire, Honeycomb, Datadog, OTLP), suppressing telemetry for sensitive code, or when tempted to call trace.set_tracer_provider() inside app code to set up instrumentation.

Use when a Shiny for Python (py-shiny) app needs to save and restore its state - shareable URLs that reproduce the current inputs, restoring state after a page refresh, persisting session state to the server, excluding inputs from saved state, or when tempted to hand-roll query-string parsing or a custom persistence layer to remember input values.

Walk through the full Shiny for Python release train interactively, phase by phase. Use when the user says "release", "start a release", "py-shiny release", "release train", or wants to publish new versions of py-shiny and its ecosystem packages (py-htmltools, py-shinyswatch, py-shinywidgets, shinylive, py-shinylive, r-shinylive). Guides through version bumps, CI checks, tagging, PyPI publishing, conda-forge, Huggingface, site updates, and blog post publication.

Manage GitHub sub-issues using the gh-sub-issue extension. Use when the user asks to create, list, add, or remove sub-issues (child issues) from a parent issue.

Comprehensive guide for porting UI components from R's bslib package to py-shiny. Use this skill when: (1) User asks to "port this feature" or "port a component" and mentions bslib or links to a bslib PR (e.g., github.com/rstudio/bslib/pull/...), (2) Porting a new component from bslib to py-shiny, (3) Adding a new input, output, or UI component that exists in bslib, (4) Implementing feature parity with bslib, (5) Working on bslib-related features or components. Covers the complete workflow including understanding source implementation, creating Python equivalents, vendoring assets (SCSS, CSS, JavaScript), creating tests, documentation, and all necessary project files.