A Python library guide for building interactive dashboards, data tools, and web applications with widgets, charts, tables, and text. It lets developers create these applications without writing JavaScript.

Use it to build dashboards, reactive data apps, widget-based tools, and server-side Python web applications, then serve and test them.

It helps organize interactive application state and behavior so components do not flicker or become difficult to maintain as the app grows.

panel — Skill for Claude Code and Codex by holoviz-dev

Install

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.

Any agent

npx skills add holoviz-dev/holoviz-skills --skill panel

Clone the repo

git clone --depth 1 https://github.com/holoviz-dev/holoviz-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/holoviz-dev/holoviz-skills/panel/github.svg)](https://agentmods.dev/skills/holoviz-dev/holoviz-skills/panel)

Your own site

<a href="https://agentmods.dev/skills/holoviz-dev/holoviz-skills/panel"><img src="https://agentmods.dev/badge/skills/holoviz-dev/holoviz-skills/panel/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/holoviz-dev/holoviz-skills/panel"><img src="https://agentmods.dev/badge/skills/holoviz-dev/holoviz-skills/panel.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,720 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What 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 5.1	$0.00049	$0.03720
Opus 5	$0.00024	$0.01860
Sonnet 5	$0.00010	$0.00744
Haiku 4.5	$0.00005	$0.00372

Measured 10d ago against content hash 1a633e7429f6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

panel 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 10d ago.

The scan reads SKILL.md. This mod also ships 7 executable files (examples/dashboard.py, examples/graphic_story.py, examples/wizard.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

developing-with-holoviz/skills/panel/SKILL.md · 161 lines

How it starts

The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Panel

Panel is a Python library for building interactive dashboards, data apps, and tools entirely in Python — no JavaScript required. It connects widgets to plots, tables, and text with reactive callbacks, and serves the result as a web application.

Always use a pn.viewable.Viewer class to structure apps. This keeps state, layout, and logic organized and avoids flickering from recreated components. Once an app outgrows one class — multiple views over shared data, state several components touch — split it into composable classes (see Designing Panel Architecture).

References — iterative development, Material UI, plotting, data storytelling, custom components, React shells, Playwright testing, app structure & scaling, review
Lookup — component docs URLs and site search
Viewer Class Pattern
Widgets and Extensions
Defaults
Templates and Layouts
Serving Workflow
Performance

References

Read these for specialized topics. Each is a standalone document you can load on demand.

Iterating on Panel Apps — pre-flight lint, serve with logging, panel-live-server MCP tools, live-browser layout lint, Bokeh plot-model inspection, startup benchmarking, screenshot with Playwright, review and debug agentic loop
Designing Panel Architecture — composing larger apps (State/DataStore/View/App, param.ClassSelector, cross-object @param.depends, from_data, pn.rx) and runtime/scale (per-session model, pn.state scheduling, URL state sync, generator streaming, caching tiers, nthreads, profiling)
Building Custom Components — Python-vs-JS decision ladder; pure-Python Viewer/PyComponent; JSComponent, ReactComponent, AnyWidgetComponent, MaterialUIComponent; CDN selection, event handling, state sync lifecycle
Wrapping React Apps — making an existing React/JSX UI the whole app: shell/app class split, model.useState as the only transport, Child embedding of Panel components, request/response param pairs, shadow-DOM CSS rules, _importmap externals, panel compile and the dev-vs-production bundle trap
Using Material UI — building pmui apps (pmui.Page, Container/Grid layouts, centering, component gotchas) and theming (theme_config palette, typography, icons, brand assets, chart theming)
Migrating to Material UI — converting an existing plain-Panel app to pmui: template→Page, widget swaps, pane/interaction upgrades, what to leave alone
Converting Designs to Material UI — workflow for turning a screenshot/design/React app into a pmui app: capture references, map to components, build component-first with mock data, assemble, theme last
Plotting in Panel — embedding plots from any library: HoloViews/hvPlot (DynamicMap zoom/pan, responsive sizing), Matplotlib, Plotly, ECharts, Bokeh toolbar tools
Data Storytelling — assembling explanatory charts into a scrollable editorial article (pmui masthead, narrow reading column, prose-then-chart rhythm, one visual family); see examples/graphic_story.py
Using Tabulator — add_filter with widgets, checkbox selection, row content, function-based filtering
Using Pytest Playwright — serve_component/wait_until utilities, JS↔Python sync tests, complete test patterns for custom components
Reviewing Panel Apps — anti-pattern checklist for code review: flickering, missing hold, watcher gaps, reactive-wiring priority, from_param super() ordering, mutation bugs
Troubleshooting Panel Apps — symptom→cause→fix for apps that serve but misbehave silently: init ordering, dead-app, blank Page, responsive/spinner issues, version & deprecation diagnosis

Read the full file on GitHub · 161 lines

Files

What ships with it

20 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

10d ago First seen · 161 lines · 49 tokens per session scan A 1a633e7429f6

Subscribe to this mod's changes

panel is a skill published in the GitHub repository holoviz-dev/holoviz-skills (5 stars, last pushed yesterday), licensed BSD-3-Clause. It adds 49 tokens to every session and 3,720 once invoked, about $0.0002 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 2026-08-31.

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