canvas

canvas is a skill for Claude Code, Codex from Bitterbot-AI/bitterbot-desktop. It costs 57 tokens per session (1,521 once invoked), scanned A, original, MIT.

A tool for showing and controlling HTML pages on connected Mac, iPhone, iPad, and Android devices. It uses a host server and device connections to display games, dashboards, visualizations, and interactive demos.

In plain words
What is it for?
Displaying HTML content, sending pages to connected devices, navigating canvas URLs, capturing snapshots, and troubleshooting device connectivity.
Why use it?
It lets you present or debug web content on connected devices without opening and navigating to each page manually.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Not installable: its command points at a path on the author’s own machine, so it runs nowhere else. The line is /Users/you/bitterbot/canvas.

Good fit Displaying HTML content, sending pages to connected devices, navigating canvas URLs, capturing snapshots, and troubleshooting device connectivity.

Compare 6 skills from other repositories ↓
About the project

Bitterbot is a local-first personal AI agent that runs on a user’s devices, keeps persistent memories, performs tasks, and can exchange reusable skills with other agents. It is intended for people who want a personal assistant that remains available across conversations and activities. The catalogue entries provide instructions and agents for working with Bitterbot.

Bitterbot-AI/bitterbot-desktop · 2,461 stars · on GitHub · bitterbot.ai

Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

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.

agentmods badge for canvas

README.md
[![agentmods](https://agentmods.dev/badge/skills/bitterbot-ai/bitterbot-desktop/canvas/github.svg)](https://agentmods.dev/skills/bitterbot-ai/bitterbot-desktop/canvas)
Your own site
<a href="https://agentmods.dev/skills/bitterbot-ai/bitterbot-desktop/canvas"><img src="https://agentmods.dev/badge/skills/bitterbot-ai/bitterbot-desktop/canvas/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 canvas

Your own site · 80×15
<a href="https://agentmods.dev/skills/bitterbot-ai/bitterbot-desktop/canvas"><img src="https://agentmods.dev/badge/skills/bitterbot-ai/bitterbot-desktop/canvas.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,521 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00057 $0.01521
Opus 5 $0.00028 $0.00760
Sonnet 5 $0.00011 $0.00304
Haiku 4.5 $0.00006 $0.00152

Measured 9d ago against content hash 28f5b129d343, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

canvas scanned grade A with 1 finding 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 9d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

3. Test URL directly: `curl http://<hostname>:18793/__bitterbot__/canvas/<file>.html`
skills/canvas/SKILL.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Canvas

Display HTML content on connected Bitterbot nodes (Mac app, iOS, Android).

Overview

The canvas tool lets you present web content on any connected node's canvas view. Great for:

  • Displaying games, visualizations, dashboards
  • Showing generated HTML content
  • Interactive demos

How It Works

Architecture

┌─────────────────┐     ┌──────────────────┐     ┌─────────────┐
│  Canvas Host    │────▶│   Node Bridge    │────▶│  Node App   │
│  (HTTP Server)  │     │  (TCP Server)    │     │ (Mac/iOS/   │
│  Port 18793     │     │  Port 18790      │     │  Android)   │
└─────────────────┘     └──────────────────┘     └─────────────┘
  1. Canvas Host Server: Serves static HTML/CSS/JS files from canvasHost.root directory
  2. Node Bridge: Communicates canvas URLs to connected nodes
  3. Node Apps: Render the content in a WebView

Tailscale Integration

The canvas host server binds based on gateway.bind setting:

Bind Mode Server Binds To Canvas URL Uses
loopback 127.0.0.1 localhost (local only)
lan LAN interface LAN IP address
tailnet Tailscale interface Tailscale hostname
auto Best available Tailscale > LAN > loopback

Key insight: The canvasHostHostForBridge is derived from bridgeHost. When bound to Tailscale, nodes receive URLs like:

http://<tailscale-hostname>:18793/__bitterbot__/canvas/<file>.html

This is why localhost URLs don't work - the node receives the Tailscale hostname from the bridge!

Actions

Action Description
present Show canvas with optional target URL
hide Hide the canvas
navigate Navigate to a new URL
eval Execute JavaScript in the canvas
snapshot Capture screenshot of canvas

Read the full file on GitHub · 205 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. 9d ago First seen · 205 lines · 57 tokens per session scan A 28f5b129d343

Subscribe to this mod's changes

canvas is a skill published in the GitHub repository Bitterbot-AI/bitterbot-desktop (2,461 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 1,521 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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