Borrowing it
Nothing to install: this file belongs to tellahq/opensession. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/tellahq/opensession/main/.agents/skills/control-ui/SKILL.mdgit clone --depth 1 https://github.com/tellahq/opensessionWrote 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/tellahq/opensession/control-ui)<a href="https://agentmods.dev/skills/tellahq/opensession/control-ui"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/control-ui/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/tellahq/opensession/control-ui"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/control-ui.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00049 | $0.01042 |
| Opus 5.5 | $0.00020 | $0.00417 |
| Sonnet 5.5 | $0.00010 | $0.00208 |
| Haiku 4.5 | $0.00005 | $0.00104 |
Grade A, and why
control-ui 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 1mo 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 — 114 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Control UI
Use local browser automation to verify UI behavior with evidence. First reuse the repo's own Playwright, browser, or Electron harness if it exists; otherwise assemble a temporary local harness around the app's dev server or Chromium debug port.
What It Is Used For
- Reproducing UI bugs that depend on real browser focus, keyboard input, scrolling, resizing, or rendering.
- Verifying visual or accessibility changes with screenshots and snapshots.
- Checking local web, IDE, or Electron behavior before shipping.
- Capturing console logs, network logs, CPU profiles, traces, or heap snapshots.
- Creating before/after evidence for
verify-this.
Setup Pattern
- Start the app locally using the repo's documented dev command.
- Discover existing local harnesses: Playwright tests, Cypress specs, Storybook, browser scripts, Electron launch scripts, or snapshot tools.
- For a web app, connect to the local URL with the existing browser tooling.
- For Electron/Chromium, enable a remote debugging port when supported.
- Select the correct page by stable app markers, not by tab order alone.
- Prefer accessibility roles, labels, and stable
data-*selectors over coordinates.
Generic Web Harness
Use the repo's installed browser tooling when possible. If the repo already has Playwright, a minimal one-off probe looks like:
import { chromium } from "playwright";
const browser = await chromium.launch();
const page = await browser.newPage({ viewport: { width: 1280, height: 800 } });
await page.goto("http://127.0.0.1:<port>");
await page.getByRole("button", { name: /submit/i }).click();
await page.screenshot({ path: "/tmp/ui-harness-after.png", fullPage: true });
await browser.close();
Do not add Playwright as a project dependency just for this probe unless the user asks. Prefer existing dev dependencies or external browser tools already available in the environment.
Generic CDP Harness
For Electron or a Chromium app launched with --remote-debugging-port=<port>, connect over CDP:
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.
- 1mo ago First seen · 114 lines · 49 tokens per session scan A 40775510557e
control-ui is a skill published in the GitHub repository tellahq/opensession (399 stars, last pushed today), licensed MIT. It adds 49 tokens to every session and 1,042 once invoked, about $0.0002 per session on Opus 5.5. 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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