screen-annotation

screen-annotation is a skill for Claude Code, Codex from vellum-ai/vellum-assistant. It costs 15 tokens per session (1,845 once invoked), scanned A, original, MIT.

A screen-sharing aid that draws a ring around something the user is showing. It points things out without clicking, typing, or controlling the computer.

In plain words
What is it for?
Use it during demonstrations or support calls to point at buttons, fields, and other visible areas of a shared screen.
Why use it?
It lets someone explain where a control is while leaving the screen usable for the person watching.

Skill for Claude CodeCodex

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

Good fit Use it during demonstrations or support calls to point at buttons, fields, and other visible areas of a shared screen.

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Install with agentmods
npx agentmods add skills/vellum-ai/vellum-assistant/screen-annotation
About the project

Vellum Assistant is a personal AI assistant that remembers information about users, learns their preferences, and takes actions across connected apps. It is intended for people who want an assistant that can manage conversations, unfinished work, and proactive notifications over time. The catalogue skills, hooks, instruction, and setting configure or extend how the assistant works.

vellum-ai/vellum-assistant · 1,234 stars · on GitHub · vellum.ai

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.

Any agent
npx skills add vellum-ai/vellum-assistant --skill screen-annotation
Clone the repo
git clone --depth 1 https://github.com/vellum-ai/vellum-assistant

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 screen-annotation

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/vellum-ai/vellum-assistant/screen-annotation"><img src="https://agentmods.dev/badge/skills/vellum-ai/vellum-assistant/screen-annotation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,845 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 $0.00015 $0.01845
Opus 5 $0.00008 $0.00923
Sonnet 5 $0.00003 $0.00369
Haiku 4.5 $0.00002 $0.00185

Measured today against content hash 77e598ad7c39, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

screen-annotation 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 today.

The scan reads SKILL.md. This mod also ships 3 executable files (tools/screen-annotation.test.ts, tools/screen-clear-marks.ts, tools/screen-point-at.ts), 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.

assistant/src/config/bundled-skills/screen-annotation/SKILL.md · 155 lines

How it starts

The opening of the file, as written. The whole thing — 155 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Drawing on the screen the user is showing you, so they can go and do the thing themselves.

This is the opposite errand from computer use. Nothing here clicks, types or drives anything: the marks are a way of pointing while you talk, for someone who wants to learn where a control is rather than have it operated for them. A mark is drawn clear of what it indicates and never takes the mouse, so what you point at stays visible and clickable the whole time.

Requires a screen share

Marks are drawn on the frame around the surface the user is sharing with the call. With nothing shared there is nowhere to draw, and screen_point_at fails saying so. Ask them to share their screen from the call, then point.

Say what to point at

Name the thing. {"target": "color balance", "caption": "Click this"}. The name is looked up on the surface itself, which knows where its controls actually are, and an arrow is drawn at it.

The label, not a description of it. What is matched is the control's own name. Casing, spacing and punctuation are forgiven, so Color Balance finds color balance; nothing beyond that is, so "the stabilization button" finds nothing, because no control is called that. Give the label on its own: stabilization, Send, Search.

The arrow points at the middle of the control and stops just short, so what you are sending someone to stays visible the whole time.

You are answered with what was drawn and the name it resolved to, which is not always the name you asked for. Say the resolved one out loud: it is the word the user can see.

A name the surface does not carry draws nothing and comes back with the names it does carry. That is the answer, not a setback: the thing is nearly always one of those, so read the list and point again. Never fall back to coordinates for a control you could not find. A mark drawn at a guess is worse than no mark, because someone follows it; the words you say are the better tool for a thing you cannot point at. What the user calls something and what the surface calls it often differ, which is what the list is for: they may say "white balance" where the control reads color balance, or "the stabilization button" where it reads stabilization.

Read the full file on GitHub · 155 lines

Files

What ships with it

4 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. today Changed · +7 lines 77e598ad7c39
  2. 2d ago Changed · +67 lines 87594f82c738
  3. 4d ago First seen · 81 lines · 15 tokens per session scan A fd5cf44ebdb8

Subscribe to this mod's changes

screen-annotation is a skill published in the GitHub repository vellum-ai/vellum-assistant (1,234 stars, last pushed today), licensed MIT. It adds 15 tokens to every session and 1,845 once invoked, about $0.0001 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 2026-09-08.

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