Borrowing it
Nothing to install: this file belongs to PostHog/posthog-foss. 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/PostHog/posthog-foss/master/.agents/skills/instrumenting-first-party-metrics/SKILL.mdgit clone --depth 1 https://github.com/PostHog/posthog-fossWrote 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/posthog/posthog-foss/instrumenting-first-party-metrics)<a href="https://agentmods.dev/skills/posthog/posthog-foss/instrumenting-first-party-metrics"><img src="https://agentmods.dev/badge/skills/posthog/posthog-foss/instrumenting-first-party-metrics/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/posthog/posthog-foss/instrumenting-first-party-metrics"><img src="https://agentmods.dev/badge/skills/posthog/posthog-foss/instrumenting-first-party-metrics.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 Prompt Injection · line 14 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 14 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
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 | $0.00134 | $0.01990 |
| Opus 5 | $0.00067 | $0.00995 |
| Sonnet 5 | $0.00027 | $0.00398 |
| Haiku 4.5 | $0.00013 | $0.00199 |
Grade A, and why
instrumenting-first-party-metrics 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 6d 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 — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Instrumenting first-party metrics
Goal: get application metrics from PostHog's own code into the PostHog Metrics product (posthog.metrics table, Metrics UI), the same way customers do.
Follow the public docs wherever possible; use OTel only as the fallback when the SDK path isn't available in your environment.
Never invent env vars or hand-roll OTel providers — every environment below already has a working path.
Step 1 — identify the environment and pick the path
| Where you are | First choice | Fallback |
|---|---|---|
| Monorepo Python (web, Celery, Temporal) | SDK: posthoganalytics.default_client.metrics — IF the pinned version supports it (see version gates) |
OtelInstrumentFactory in posthog/otel_metrics.py |
Monorepo Node services (nodejs/) |
— (services don't run posthog-node) | internal twin: nodejs/src/common/metrics/otel-metrics.ts |
| PostHog-owned standalone service / script / other repo | SDK per public docs: posthog.metrics.count/gauge/histogram |
OTLP env vars per docs (OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=<host>/i/v1/metrics, Bearer project token) |
[!WARNING] In a Temporal worker the OTel fallback is not a fallback — it is silence.
OTEL_METRICS_EXPORT_URL/_TOKENare set on the web deployment, not on the worker deployments, soOtelInstrumentFactorybinds a no-op meter there and every twin is dropped. No metric recorded through the factory from a worker activity has ever reached the Metrics product, while SDK-path metrics from the same pods do. From a worker, use the SDK path or the Temporal metric meter.Do not assume the
prometheus_clienthalf of a twin covers for the dropped twin, and do not drop the instrument either.create_workerstartsCombinedMetricsServerby default (enable_combined_metrics_server=True, fromTEMPORAL_COMBINED_METRICS_SERVER_ENABLED), and that server serves the Python registry next to the Temporal SDK's own metrics on the worker's metrics port. So the registry is exported by default, but it reaches Grafana only if the combined server is still enabled and the deployment scrapes that endpoint. Both are deployment configuration outside this repository, so confirm them before you rely on aprometheus_clientinstrument as a worker's only sink.
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.
- 6d ago Changed · +10 lines f1ced69ed1e4
- 12d ago First seen · 75 lines · 134 tokens per session scan A fc0a948b6760
instrumenting-first-party-metrics is a skill published in the GitHub repository PostHog/posthog-foss (715 stars, last pushed today), licensed MIT. It adds 134 tokens to every session and 1,990 once invoked, about $0.0007 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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