html-skills-listen

html-skills-listen is a skill for Claude Code from f-labs-io/agent-html-skills. It costs 86 tokens per session (1,104 once invoked), scanned A, original, MIT.

A local receiver for interactive HTML artifacts, which are browser-based files that collect user input. It sends each submission back to the current session as a notification.

In plain words
What is it for?
Use it when an interactive HTML skill needs a per-session server and a URL for receiving submissions.
Why use it?
It avoids asking users to copy and paste their responses after using an interactive artifact.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: mentions Claude Code.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the html-skills plugin — 19 skills shipped together

Good fit Use it when an interactive HTML skill needs a per-session server and a URL for receiving submissions.

Compare 6 skills from other repositories ↓
Install

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.

Claude Code
/plugin marketplace add f-labs-io/agent-html-skills
Claude Code
/plugin install html-skills

Made for: Claude Code.

Or install html-skills, the plugin that ships this one along with the rest of its 19 skills.

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.

agentmods badge for html-skills-listen

README.md
[![agentmods](https://agentmods.dev/badge/skills/f-labs-io/agent-html-skills/html-skills-listen/github.svg)](https://agentmods.dev/skills/f-labs-io/agent-html-skills/html-skills-listen)
Your own site
<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.

agentmods 80×15 button for html-skills-listen

Your own site · 80×15
<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>
Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,104 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.

ModelPer sessionOnce 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

Measured 7d ago against content hash e05f6a37176d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

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.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/listen.sh, server.js), 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.

plugins/html-skills/skills/html-skills-listen/SKILL.md · 74 lines

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

  1. 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=VALUE lines. Always present: SID, LOG, MIDF, STATUS. With STATUS=STARTED or STATUS=ALREADY_RUNNING you also get URL. After a restart of a receiver that had died, STATUS=STARTED also prints RESTARTED=1 and, if its previous port could not be reused, PORT_CHANGED=1.

  2. Branch on STATUS:

    • STATUS=WEB — Claude Code web session; the sandbox can't reach the user's browser. Don't arm a Monitor. 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 — the Monitor was armed when this session's receiver first started; don't arm another. Return URL to the parent skill and stop.

    • STATUS=STARTED — continue to step 3.

  3. Arm a persistent Monitor on the receiver's log. Substitute the literal LOG value into the command (the Monitor tool 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
    )
    

Read the full file on GitHub · 74 lines

Files

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.

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.

  1. 7d ago Changed · +4 lines · -75 tokens per session e05f6a37176d
  2. 11d ago First seen · 70 lines · 161 tokens per session scan A 54145d12cbd8

Subscribe to this mod's changes

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.

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