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.
npx skills add PracticalSwan/agent-skills --skill codex-in-app-browsergit clone --depth 1 https://github.com/PracticalSwan/agent-skillsWrote 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/practicalswan/agent-skills/codex-in-app-browser)<a href="https://agentmods.dev/skills/practicalswan/agent-skills/codex-in-app-browser"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/codex-in-app-browser.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Prompt Injection · line 55 Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
- medium Agent Snooping · line 16 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 | $0.00111 | $0.01070 |
| Opus 5 | $0.00056 | $0.00535 |
| Sonnet 5 | $0.00022 | $0.00214 |
| Haiku 4.5 | $0.00011 | $0.00107 |
Grade A, and why
codex-in-app-browser 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.
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 — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codex In-App Browser
The tool is mcp__node_repl__js. It is available in this session.
First: read the official skill
The official skill is authoritative. Read it before any browser work:
~/.codex/plugins/cache/openai-bundled/browser/<version>/skills/control-in-app-browser/SKILL.md
Find the latest <version> directory (for example 26.803.41515).
Bootstrap (once per session)
Send this as ONE line through mcp__node_repl__js:
if (globalThis.agent?.browsers == null) { const { setupBrowserRuntime } = await import("<plugin root>/scripts/browser-client.mjs"); globalThis.agent = await setupBrowserRuntime(); }
Replace <plugin root> with the browser plugin path. Then bind the
in-app browser and read its documentation:
globalThis.iab = await agent.browsers.get("iab");
nodeRepl.write(await iab.documentation());
Read the complete documentation output before interacting with the page.
Rules
- Send code as ONE line, or use
@file:<path>with a trailing newline. The runtime fires on newline; input without a trailing newline silently does nothing. - Reuse the existing
agentandiabbindings on later turns. Do not reinitialize. open_in_codexonly OPENS a tab. It cannot click, type, or read. Usemcp__node_repl__jsfor interaction.- Never start your own node_repl process and never write a side-channel driver. Use the tool you were given.
If the tool is missing
Stop and report that mcp__node_repl__js is not in the tool list. Do not
build workarounds.
Cross-Client Portability
This skill is written to stay usable across GitHub Copilot, Claude Code, and Codex.
- GitHub Copilot: keep the folder in a Copilot-visible skill path or wrap the workflow in project instructions when folder discovery is unavailable.
- Claude Code: keep the folder in a local skills directory or a compatible plugin source.
- Codex: install or sync the folder into
$CODEX_HOME/skills/codex-in-app-browserand restart Codex after major changes.
What ships with it
1 file 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.
- today Changed 9174f76755ad
- yesterday Changed eaca1f202cbc
- 4d ago Changed b1d0e9b62fd4
- 8d ago First seen · 103 lines · 111 tokens per session scan A 6f2f577093d0
codex-in-app-browser is a skill published in the GitHub repository PracticalSwan/agent-skills (13 stars, last pushed today), licensed MIT. It adds 111 tokens to every session and 1,070 once invoked, about $0.0006 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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