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/measure-telemetry-span/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/measure-telemetry-span)<a href="https://agentmods.dev/skills/expensify/app/measure-telemetry-span"><img src="https://agentmods.dev/badge/skills/expensify/app/measure-telemetry-span/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/measure-telemetry-span"><img src="https://agentmods.dev/badge/skills/expensify/app/measure-telemetry-span.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, 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 Agent Snooping · line 57 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 | $0.00029 | $0.02343 |
| Opus 5.5 | $0.00012 | $0.00937 |
| Sonnet 5.5 | $0.00006 | $0.00469 |
| Haiku 4.5 | $0.00003 | $0.00234 |
Grade A, and why
measure-telemetry-span 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 — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Measure Telemetry Span
Pattern: from repo root, run one command with a span name and platform → stdout is a small summary table (avg / min / max + sample ms list). The script measures whatever Git checkout is currently active: it never runs git checkout or otherwise switches branches. To compare this branch with main (or any other revision), check out each commit/branch in turn—or use two worktrees/clones—and run measure.sh separately, then compare the two printed summaries.
Layout
measure-telemetry-span/
├── measure.sh # the runner
├── flows/ # one .ad flow per measured journey
└── scripts/replay-with-deadline.mjs # wall-clock deadline around `agent-device replay`
Each flow under flows/ declares the spans it owns with # @span <SpanName> and names the span the runner looks up. Flows here do not own application lifecycle, so they are not inputs for agent-device test; the runner opens the app and prepares the session.
Setup and navigation helpers live in .claude/skills/agent-device/flows/macros/, and @reset headers point at them. The .ad metadata spec, selector rules, and recording workflow live in agent-device/flows/README.md — read it before adding or healing a flow here.
Command
.claude/skills/measure-telemetry-span/measure.sh <span-name> [runs] [platform] [--boot]
| Argument | Default | Description |
|---|---|---|
<span-name> |
— | Must match # @span <span-name> on a flow under .claude/skills/measure-telemetry-span/flows/. |
[runs] |
10 |
Measured replays after one warmup inside the script. |
[platform] |
ios |
ios or android — must match the simulator/emulator you use. |
--boot |
off | Before open, runs agent-device boot --platform <platform> so a simulator/emulator is started when nothing was connected (adb devices empty, etc.). |
What ships with it
12 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.
- flows/create-expense-manual.ad 2.2 KB
- flows/open-create-expense.ad 992 B
- flows/open-report.ad 853 B
- flows/open-search-router.ad 614 B
- flows/scan-receipt-init.ad 1021 B
- flows/send-message.ad 1.1 KB
- flows/submit-expense.ad 1010 B
- flows/switch-home-to-inbox.ad 1011 B
- flows/switch-home-to-reports.ad 730 B
- measure.sh 11 KB runs code
- scripts/replay-with-deadline.mjs 3.8 KB runs code
- scripts/replay-with-deadline.test.mjs 4.3 KB runs code
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 Changed · +43 lines ffe1721bbc30
- 2mo ago First seen · 70 lines · 29 tokens per session scan A 5c6714c57cd3
measure-telemetry-span is a skill published in the GitHub repository Expensify/App (5,081 stars, last pushed today), licensed MIT. It adds 29 tokens to every session and 2,343 once invoked, about $0.0001 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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