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 rudderlabs/rudder-agent-skills --skill rudder-design-first-instrumentationgit clone --depth 1 https://github.com/rudderlabs/rudder-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/rudderlabs/rudder-agent-skills/rudder-design-first-instrumentation)<a href="https://agentmods.dev/skills/rudderlabs/rudder-agent-skills/rudder-design-first-instrumentation"><img src="https://agentmods.dev/badge/skills/rudderlabs/rudder-agent-skills/rudder-design-first-instrumentation/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/rudderlabs/rudder-agent-skills/rudder-design-first-instrumentation"><img src="https://agentmods.dev/badge/skills/rudderlabs/rudder-agent-skills/rudder-design-first-instrumentation.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 | $0.00037 | $0.02291 |
| Opus 5 | $0.00018 | $0.01145 |
| Sonnet 5 | $0.00007 | $0.00458 |
| Haiku 4.5 | $0.00004 | $0.00229 |
Grade A, and why
rudder-design-first-instrumentation 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 12d 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 — 375 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design-First Instrumentation
This skill guides instrumentation planning for new features where events are defined during product definition, before implementation begins.
When to Use This Skill
| Scenario | Use This Skill? |
|---|---|
| Building a new feature, events not yet defined | Yes |
| Product requirements include analytics needs | Yes |
| PM and engineering collaborating on what to track | Yes |
| Existing product needs instrumentation | No — use rudder-code-first-instrumentation |
| Restructuring existing tracking | No — use rudder-code-first-instrumentation |
The Design-First Workflow
┌─────────────────────────────────────────────────────────────────────┐
│ DESIGN-FIRST INSTRUMENTATION │
└─────────────────────────────────────────────────────────────────────┘
│
▼
┌─────────────────┐
│ 1. REQUIREMENTS │ ← What questions must the data answer?
└────────┬────────┘
▼
┌─────────────────┐
│ 2. EVENT DESIGN │ ← Define events (names only, no properties yet)
└────────┬────────┘
▼
┌─────────────────┐
│ 3. HUMAN │ ← PM/Eng review: Are these the right events?
│ CHECKPOINT │
└────────┬────────┘
▼
┌─────────────────┐
│ 4. PROPERTY │ ← Define properties for approved events
│ DESIGN │
└────────┬────────┘
▼
┌─────────────────┐
│ 5. BUILD YAML │ ← Create tracking plan definitions
└────────┬────────┘
▼
┌─────────────────┐
│ 6. IMPLEMENT │ ← Code the feature with instrumentation
└─────────────────┘
Phase 1: Requirements Gathering
Start with the questions the data must answer:
Questions Template
## Feature: [Feature Name]
### Business Questions
- [ ] What is the conversion rate through this feature?
- [ ] Where do users drop off?
- [ ] How long does it take users to complete the flow?
- [ ] What variations do users prefer?
### Success Metrics
- Primary: _______________
- Secondary: _______________
### Funnel Stages
1. Entry point: _______________
2. Key action: _______________
3. Completion: _______________
### Stakeholders
- PM: _______________
- Engineering: _______________
- Data/Analytics: _______________
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.
- 12d ago First seen · 375 lines · 37 tokens per session scan A 1106422ad0ab
rudder-design-first-instrumentation is a skill published in the GitHub repository rudderlabs/rudder-agent-skills (18 stars, last pushed 7d ago), licensed MIT. It adds 37 tokens to every session and 2,291 once invoked, about $0.0002 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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