Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/posit-dev/py-shiny/copilot-instructionsgit clone --depth 1 https://github.com/posit-dev/py-shinyWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.05124 | $0.05124 |
| Opus 5 | $0.02562 | $0.02562 |
| Sonnet 5 | $0.01025 | $0.01025 |
| Haiku 4.5 | $0.00512 | $0.00512 |
Grade A, and why
py-shiny copilot-instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 764 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GitHub Copilot Instructions for py-shiny
This document provides GitHub Copilot with comprehensive context about the Shiny for Python repository to help generate high-quality, context-aware code and suggestions.
1. Project Overview
Shiny for Python is a framework for building fast, beautiful web applications in Python. It enables data scientists and developers to create interactive visualizations and applications quickly while remaining extensible enough to power large, mission-critical applications.
Key Principles
- Reactive Programming: Automatic dependency tracking and efficient updates
- Extensibility: Build simple prototypes or complex production applications
- Performance: Optimized for speed and efficiency
- Developer Experience: Intuitive APIs with both Express (simple) and Core (powerful) modes
Documentation
- Main documentation: https://shiny.posit.co/py/
- API reference: https://shiny.posit.co/py/api/
- Learn more: https://shiny.posit.co/py/docs/overview.html
2. Repository Structure
py-shiny/
├── shiny/ # Core library code
│ ├── express/ # Express API (decorator-based, simpler syntax)
│ ├── ui/ # UI components and page layouts
│ ├── render/ # Rendering functions (@render.plot, @render.table, etc.)
│ ├── reactive/ # Reactive programming primitives (@reactive.calc, @reactive.effect)
│ ├── session/ # Session management
│ ├── experimental/ # Experimental features
│ ├── api-examples/ # API documentation examples
│ └── templates/ # Project templates
├── tests/ # Test suite
│ ├── pytest/ # Unit tests
│ └── playwright/ # End-to-end integration tests
├── examples/ # Example applications
├── docs/ # Documentation source (Quartodoc + Quarto)
├── js/ # JavaScript/TypeScript code
└── scripts/ # Development and build scripts
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 764 lines · 5,124 tokens per session scan A 97aac7b7c444
py-shiny copilot-instructions.md is an instructions file published in the GitHub repository posit-dev/py-shiny (1,750 stars, last pushed today), licensed MIT. It adds 5,124 tokens to every session, about $0.0256 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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