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 PostHog/posthog-foss --skill grouping-noisy-errorsgit 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/grouping-noisy-errors)<a href="https://agentmods.dev/skills/posthog/posthog-foss/grouping-noisy-errors"><img src="https://agentmods.dev/badge/skills/posthog/posthog-foss/grouping-noisy-errors/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/grouping-noisy-errors"><img src="https://agentmods.dev/badge/skills/posthog/posthog-foss/grouping-noisy-errors.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 | $0.00112 | $0.03113 |
| Opus 5 | $0.00056 | $0.01556 |
| Sonnet 5 | $0.00022 | $0.00623 |
| Haiku 4.5 | $0.00011 | $0.00311 |
Grade A, and why
grouping-noisy-errors 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 9d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- grouping-noisy-errors — 86% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 304 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Grouping noisy errors
The same error can be reported as dozens of separate issues when stack frames or messages contain volatile data — random IDs, dynamic file paths, build hashes, anonymous function names. The fix is two-step: merge the existing issues into one target, then create a grouping rule so future events from the same call site share a single canonical fingerprint instead of spawning new ones.
Important up front: "same error" here is narrow. Two issues that share a name or
a sentence of message text but came from different code paths, different SDKs,
or different runtimes are different errors and should stay separate, even if
the user thinks of them as "the same kind of bug". Grouping a frontend
TypeError together with a backend TypeError because both messages contain
"undefined" destroys the signal that lets the team find each one. The criteria
in step 1 exist to keep that from happening.
Available tools
| Tool | Purpose |
|---|---|
posthog:query-error-tracking-issues-list |
Find candidate duplicate issues |
posthog:query-error-tracking-issue |
Pull compact details for an individual issue |
posthog:query-error-tracking-issue-events |
Sampled $exception events with stack and message |
posthog:error-tracking-issues-merge-create |
Merge existing issues into a target |
posthog:error-tracking-issues-split-create |
Surgically split fingerprints back out if a merge errs |
posthog:error-tracking-grouping-rules-create |
Auto-group future events into one issue |
posthog:error-tracking-grouping-rules-list |
Check existing grouping rules before adding new ones |
posthog:error-tracking-issues-partial-update |
Rename or re-describe the target after a merge |
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.
- 9d ago First seen · 304 lines · 112 tokens per session scan A 03d7d209c2dc
grouping-noisy-errors is a skill published in the GitHub repository PostHog/posthog-foss (715 stars, last pushed today), licensed MIT. It adds 112 tokens to every session and 3,113 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 2026-09-03.
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