Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add f-labs-io/agent-html-skills/plugin install html-skillsWrote 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.
[](https://agentmods.dev/skills/f-labs-io/agent-html-skills/html-skills-listen)<a href="https://agentmods.dev/skills/f-labs-io/agent-html-skills/html-skills-listen"><img src="https://agentmods.dev/badge/skills/f-labs-io/agent-html-skills/html-skills-listen/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.
<a href="https://agentmods.dev/skills/f-labs-io/agent-html-skills/html-skills-listen"><img src="https://agentmods.dev/badge/skills/f-labs-io/agent-html-skills/html-skills-listen.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00086 | $0.01104 |
| Opus 5 | $0.00043 | $0.00552 |
| Sonnet 5 | $0.00017 | $0.00221 |
| Haiku 4.5 | $0.00009 | $0.00110 |
Grade A, and why
html-skills-listen scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.
html-skills-listen — server-mode setup for html-skills artifacts
System primitive for the html-skills plugin. It runs a bundled script that detects the environment, starts (or finds) this session's local receiver on an ephemeral port, and prints what you need; you then arm a Monitor on the receiver's log so each submit becomes a session notification, and hand the URL back to the skill that invoked you.
Steps
-
Run the setup script with this session's id:
bash "${CLAUDE_PLUGIN_ROOT}/skills/html-skills-listen/scripts/listen.sh" "${CLAUDE_SESSION_ID}"Output is
KEY=VALUElines. Always present:SID,LOG,MIDF,STATUS. WithSTATUS=STARTEDorSTATUS=ALREADY_RUNNINGyou also getURL. After a restart of a receiver that had died,STATUS=STARTEDalso printsRESTARTED=1and, if its previous port could not be reused,PORT_CHANGED=1. -
Branch on
STATUS:-
STATUS=WEB— Claude Code web session; the sandbox can't reach the user's browser. Don't arm aMonitor. Tell the parent skill (or the user, if invoked directly):ⓘ Claude Code web session detected. Server mode can't work here. The artifact will use clipboard mode automatically — Submit copies JSON to the clipboard for paste-back.
Stop here.
-
STATUS=ERROR— report the script output (it names the cause:node-not-found,receiver-died-on-startup,no-listening-line-in-log) and stop. The parent skill proceeds in clipboard mode. -
STATUS=ALREADY_RUNNING— theMonitorwas armed when this session's receiver first started; don't arm another. ReturnURLto the parent skill and stop. -
STATUS=STARTED— continue to step 3.
-
-
Arm a persistent
Monitoron the receiver's log. Substitute the literalLOGvalue into the command (theMonitortool can't expand variables itself):Monitor( description: "html-skills artifact submissions", command: "tail -f <LOG> | grep --line-buffered '\"method\":\"notifications/claude/channel\"'", persistent: true, timeout_ms: 3600000 )
What ships with it
2 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.
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.
- 7d ago Changed · +4 lines · -75 tokens per session e05f6a37176d
- 11d ago First seen · 70 lines · 161 tokens per session scan A 54145d12cbd8
html-skills-listen is a skill published in the GitHub repository f-labs-io/agent-html-skills (55 stars, last pushed 9d ago), licensed MIT. It adds 86 tokens to every session and 1,104 once invoked, about $0.0004 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.
Other skills, from other repositories
debug-optimize-lcp
Guides debugging and optimizing Largest Contentful Paint (LCP) using Chrome DevTools MCP tools. Use this skill whenever the user asks about LCP performance, slow page loads, Core Web Vitals optimization, or wants to understand why their page's main content takes too long to appear. Also use when the user mentions…
opencli-sitemap-author
Use when creating or maintaining OpenCLI site sitemaps: agent-facing navigation, page-state, action, workflow, API-reference, pitfall, and fallback knowledge for a website. Use after browser exploration discovers durable site context, when a sitemap is stale, or when promoting local site knowledge into the repo.
interactive-login
How to complete browser/interactive logins (aws / gh / glab / gcloud). The platform backgrounds the login poller so it survives the human's browser round-trip — and when that does NOT work.
pinchtab-mcp
Use this skill when a task requires browser automation through PinchTab's MCP server connected to a remote browser instance. Covers navigation, element interaction, data extraction, form filling, multi-step flows, and session management via MCP tools.
azure-messaging-webpubsub-java
Build real-time web applications with Azure Web PubSub SDK for Java. Use when implementing WebSocket-based messaging, live updates, chat applications, or server-to-client push notifications.
google-safe-browsing
Prevent and fix Google Safe Browsing "Dangerous site" flags. Use when launching a public web app, buying/picking a domain, building a login or signup page, or when any site shows a red "Dangerous site" / "Deceptive site" warning in Chrome, Brave, Safari, Firefox, or Edge. Triggers on "dangerous site", "deceptive…