shiny-py-optimize SKILL.md skillA
shiny-py-optimize from posit-dev/skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add posit-dev/skills/shiny-py-optimize@v1.0Pins v1.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- posit-dev/skills
- Path
shiny/shiny-py-optimize/SKILL.md- Versions recorded
- 2
- Latest version
- v1.0, committed Nov 2, 2026
- First version recorded
- Oct 14, 2026
- Size
- 14,918 bytes
- Repository stars
- 556
- License
- MIT
Diagnose and fix performance problems in Shiny for Python apps — slow startup, sluggish interactions, blocking operations, and apps that struggle beyond a handful of concurrent users. Use when a Shiny for Python app is slow, hangs, recomputes too much, times out, or must support more users; when the user asks to "speed up", "optimize", or "make faster" a Python Shiny app; or when preparing a prototyped app for real-world traffic.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Optimizing Shiny for Python App Performance Make an existing Shiny for Python app faster without changing what it does. The typical user has an app that worked fine for one or two developers and is now too slow or must support more users. Keep all app logic intact; prefer code changes over deployment tuning; resist rewrites. Order of preference for every fix: 1. **Eliminate** work that isn't needed (don't compute outputs nobody is looking at; don't compute with inputs that aren't ready). 2. **Reuse** work that repeats (shared `@reactive.calc`, module-level caches). 3. **Accelerate** unavoidable work (faster data formats, polars, push-down). 4. **Relocate** work that blocks (`@reactive.extended_task`) — last resort; it buys concurrency, not raw speed. One fact drives most Python-specific advice: **every session in a process shares one asyncio event loop.** A *synchronous* blocking call in any reactive function freezes every session in the process. What a slow `async def` reactive blocks depends on the shiny version (check with `python -c "import shiny; print(shiny.__version__)"`): - **shiny < 1.9.0:** reactive functions run serially across the whole …
Read the whole file at its exact version.
How to install
mdr add posit-dev/skills/shiny-py-optimize@sha256:61cfc4ac538e7942The line at the top of this page pins the label v1.0, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_3u7keezl2ruiiqhm)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Oct 14, 2026 and Nov 2, 2026, about one every 19 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1.0 latest | 2026-11-02 | 45685aa | 14,918 B | A | view · diff |
| v1.0 | 2026-10-14 | 7cef2d7 | 14,239 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (14918 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
posit-dev/skills · 556 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_3u7keezl2ruiiqhm GET https://markdownregistry.com/api/v1/resolve?ref=posit-dev/skills/shiny-py-optimize GET https://markdownregistry.com/api/v1/blob/61cfc4ac538e794271cf50e6461c6689abf9764edecfba28f8891fa1f44ee9ff
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.