A self-contained HTML engineering plan saved as a file that can be opened in a web browser. It describes how to build a feature and can include diagrams, tables, decision trees, and interactive elements made with HTML, CSS, SVG, and JavaScript.

Use it to document implementation choices, phases, dependencies, comparisons, and technical workflows before coding.

It gives developers a richer, easier-to-browse plan than plain text while keeping everything in one file and requiring no generated images.

How disler/pi-agent-observability configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to disler/pi-agent-observability. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/disler/pi-agent-observability/main/.claude/skills/htmlspec/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/disler/pi-agent-observability

Made for: Claude Code.

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/disler/pi-agent-observability/htmlspec/github.svg)](https://agentmods.dev/skills/disler/pi-agent-observability/htmlspec)

Your own site

<a href="https://agentmods.dev/skills/disler/pi-agent-observability/htmlspec"><img src="https://agentmods.dev/badge/skills/disler/pi-agent-observability/htmlspec/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/disler/pi-agent-observability/htmlspec"><img src="https://agentmods.dev/badge/skills/disler/pi-agent-observability/htmlspec.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 123 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,115 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	$0.00123	$0.03115
Opus 5.5	$0.00049	$0.01246
Sonnet 5.5	$0.00025	$0.00623
Haiku 4.5	$0.00012	$0.00312

Measured 2mo ago against content hash 4d9687c985e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

htmlspec 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 2mo 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.

.claude/skills/htmlspec/SKILL.md · 243 lines

How it starts

The opening of the file, as written. The whole thing — 243 lines — stays where its author put it; the contents beside it link to each section on GitHub.

htmlspec

Purpose

Produce an engineering implementation plan as one self-contained, text-only HTML page — specs/<plan-name>.html — that you can open directly in a browser. Unlike a markdown spec, the plan is authored directly in HTML using the template below, and a dedicated Freeform zone lets you author any HTML you want (interactive toggles, animated SVG flows, comparison matrices, decision trees, etc.) to make the plan clearer and richer than prose could. No images are generated — all visual enrichment comes from inline HTML, CSS, SVG, and JS authored directly into the page.

Phases, in order:

Plan phase — analyze, explore, design (same thinking as a normal spec).
HTML authoring phase — write the plan into the HTML Plan Template.
Freeform phase — enrich the page with custom HTML per the Freeform Instruction Set.

Variables

USER_PROMPT: $1 ALL_ARGUMENTS: $ARGUMENTS PLAN_OUTPUT_DIRECTORY: specs/ PLAN_SLUG: kebab-case name derived from the plan topic (e.g. in-memory-ttl-lru-cache) HTML_OUTPUT: specs/htmlspec-<PLAN_SLUG>.html — the filename MUST always begin with the htmlspec- prefix

Instructions

Plan phase

IMPORTANT: If no USER_PROMPT is provided, stop and ask the user to provide it.
Carefully analyze the USER_PROMPT. Determine task type (chore|feature|refactor|fix|enhancement) and complexity (simple|medium|complex).
Think deeply (ultrathink) about the best implementation approach.
Explore the codebase to understand existing patterns and architecture.
Decide which sections from the HTML Plan Template apply (include the conditional sections only when task type/complexity warrants them, exactly like a normal spec).
Generate a descriptive kebab-case PLAN_SLUG from the topic.

HTML authoring phase

Author the plan directly in HTML using the HTML Plan Template below — do not write a markdown file. The output is a single specs/htmlspec-<PLAN_SLUG>.html.
Keep the page self-contained: all CSS inline in <style>, any JS inline in <script>, no external network/CDN dependencies unless genuinely required (and if so, note it in Notes).
Fill every applicable section with real, detailed content — the plan must be implementable by another developer. Use semantic HTML: <ul>/<ol> for lists, <table> for comparisons, <pre><code> for code/commands.
Preserve the dark visual theme defined by the template's CSS tokens so the page reads as one body of work.
Do not include any <figure>/<img> elements — this skill is text-only.

Read the full file on GitHub · 243 lines

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.

2mo ago First seen · 243 lines · 123 tokens per session scan A 4d9687c985e5

Subscribe to this mod's changes

htmlspec is a skill published in the GitHub repository disler/pi-agent-observability (148 stars, last pushed 5mo ago), licensed MIT. It adds 123 tokens to every session and 3,115 once invoked, about $0.0005 per session on Opus 5.5. 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.

Planning

htmlspec next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
htmlspecdisler/pi-agent-observability	Skill	148	5mo ago	MIT	A	123	Claude Code
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	today	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	today	MIT	A	103	Claude Code

pi-agent-observability: Skill for Claude Code