Expensify/App is the source code for New Expensify, a financial collaboration application organized around chat. It is used by contributors building and testing the web, iOS, and Android versions of the application. Catalogue add-ons support development workflows such as mobile testing and agent-assisted work on the codebase.
Borrowing it
Nothing to install: this file belongs to Expensify/App. 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/Expensify/App/main/.claude/skills/agent-device-evidence/SKILL.mdgit clone --depth 1 https://github.com/Expensify/AppWrote 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/expensify/app/agent-device-evidence)<a href="https://agentmods.dev/skills/expensify/app/agent-device-evidence"><img src="https://agentmods.dev/badge/skills/expensify/app/agent-device-evidence/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/expensify/app/agent-device-evidence"><img src="https://agentmods.dev/badge/skills/expensify/app/agent-device-evidence.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
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 →
- medium Rogue Agent · line 61 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium Rogue Agent · line 120 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00043 | $0.03491 |
| Opus 5.5 | $0.00017 | $0.01396 |
| Sonnet 5.5 | $0.00009 | $0.00698 |
| Haiku 4.5 | $0.00004 | $0.00349 |
Grade A, and why
agent-device-evidence 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 2mo 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 — 237 lines — stays where its author put it; the contents beside it link to each section on GitHub.
agent-device-evidence
Records iOS: Native and Android: Native MP4 evidence for the test or repro steps declared in an Expensify GitHub PR or issue. The source of truth is the test/repro steps themselves, not the surrounding code or context - the skill works equally well on a PR's ### Tests section, an issue's ## Action Performed: block, or any future Markdown body where steps are clearly authored.
Specializes the agent-device skill: delegates device lifecycle (bundle ID, Metro, device pick, session, open) to its Bring-up, then captures one artifact per declared flow per platform, writes a JSON manifest, and surfaces local file paths.
The skill is autonomous and non-interactive. It never pauses for user input mid-run. All inputs are provided at invocation time; all failures surface as structured errors with exit codes.
HybridApp-only (the parent skill's pre-flight enforces this). Standalone (non-HybridApp) builds are out of scope - production mobile evidence runs against HybridApp.
Scope
In scope: iOS: Native (iOS Simulator), Android: Native (Android Emulator), HybridApp dev build only. Inputs may come from PRs or issues - the skill does not gate on code changes.
Out of scope: Android: mWeb Chrome, iOS: mWeb Safari, iOS: mWeb Chrome, Windows: Chrome, MacOS: Chrome / Safari. Decline with EXIT 4 and point to a browser-driver skill (playwright-app-testing). Standalone (non-HybridApp) builds. Decline with EXIT 7 BRING_UP_FAILED per the parent skill's gate.
Inputs
| Input | Source | Required |
|---|---|---|
| Source URL (PR or issue) | First positional arg, e.g. https://github.com/Expensify/App/pull/89475 or .../issues/89855 |
Yes |
--platforms ios,android |
Flag | No (default: derived) |
-e KEY=VALUE step-param overrides |
Repeatable | No |
Bare numbers are rejected (PRs and issues share the GitHub number namespace; the URL path is the safe disambiguator). No interactive prompts.
What ships with it
3 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.
- 2mo ago First seen · 237 lines · 43 tokens per session scan A 850193f720a1
agent-device-evidence is a skill published in the GitHub repository Expensify/App (5,081 stars, last pushed today), licensed MIT. It adds 43 tokens to every session and 3,491 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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