sideshow

A plugin for publishing live HTML previews to a browser surface where the user can comment on them. It also sends those comments back so the preview can be revised.

In plain words
What is it for?
Use it to publish, update, and discuss HTML snippets when illustrating, visualizing, sketching, or drawing an interface.
Why use it?
It gives the user a direct way to inspect visual work and request changes while the work is in progress.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/modem-dev/sideshow/sideshow
Any agent
npx skills add modem-dev/sideshow --skill sideshow
Clone the repo
git clone --depth 1 https://github.com/modem-dev/sideshow

Made for: Claude Code, Codex.

Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 676 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00054 $0.00676
Opus 5 $0.00027 $0.00338
Sonnet 5 $0.00011 $0.00135
Haiku 4.5 $0.00005 $0.00068

Measured 2d ago against content hash d47ae5671ebd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sideshow 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.

plugin/skills/sideshow/SKILL.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

sideshow (plugin)

The user keeps a sideshow surface open in their browser. You publish HTML snippets to it; they appear instantly. The user comments on any snippet, and this plugin streams those comments to you as notifications — you do not poll or arm a watcher. It is a two-way surface, not a fire-and-forget renderer.

How feedback reaches you

A background monitor (sideshow watch) runs for the whole session and delivers each new user comment as a notification on your next turn, for example:

sideshow comment on “Cache layout” (snippet a1b2c3): “tighten the spacing”

Treat every such line as a message from the user. Respond by revising the snippet it refers to (update_snippet / sideshow update <id>) or replying (reply_to_user / sideshow comment). Comments are delivered exactly once — you will not see the same one twice, so act on each when it arrives. You never need to call wait_for_feedback just to stay aware of comments; the monitor already does that. (Publish/update/reply responses may still carry a userFeedback array; it is the same stream, also delivered once.)

Before your first publish

Fetch the design contract once per session (fragment rules, theme CSS variables, CDN allowlist, sizing):

  • MCP: get_design_guide
  • CLI: sideshow guide

Publishing

Prefer the MCP tools when connected (publish_snippet, update_snippet, wait_for_feedback, reply_to_user); otherwise use the CLI. Session grouping is automatic.

sideshow publish sketch.html --title "Cache layout" --session-title "Cache redesign"
echo '<p>...</p>' | sideshow publish - --title "Quick note"

Rules of thumb:

  • On your first publish, set a session title that names the task ("Auth refactor"), not the tool — sessionTitle (MCP) / --session-title (CLI). It applies only when the session is created; never retitle later (the user may have renamed it in the viewer).
  • One concept per snippet, with a clear title. A series of small snippets beats one giant page.
  • Iterate with update_snippet / sideshow update <id> (same card, new version) instead of publishing near-duplicates.
  • Use the kit from the design guide (pre-styled form elements, SVG utility classes) before writing CSS; otherwise use the theme CSS variables so snippets work in dark mode.

Read the full file on GitHub · 68 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.

  1. 2d ago First seen · 68 lines · 54 tokens per session scan A d47ae5671ebd

Subscribe to this mod's changes

sideshow is a skill published in the GitHub repository modem-dev/sideshow (567 stars, last pushed 5d ago), licensed MIT. It adds 54 tokens to every session and 676 once invoked, about $0.0003 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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