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 perniemann/pnCore --skill pn-deprecation-and-removalgit clone --depth 1 https://github.com/perniemann/pnCoreWrote 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/perniemann/pncore/pn-deprecation-and-removal)<a href="https://agentmods.dev/skills/perniemann/pncore/pn-deprecation-and-removal"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-deprecation-and-removal/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/perniemann/pncore/pn-deprecation-and-removal"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-deprecation-and-removal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00060 | $0.00746 |
| Opus 5.5 | $0.00024 | $0.00298 |
| Sonnet 5.5 | $0.00012 | $0.00149 |
| Haiku 4.5 | $0.00006 | $0.00075 |
Grade A, and why
pn-deprecation-and-removal 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 — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Deprecation and removal
When to use
- Replacing a public API, SDK surface, REST route, or config key
- Removing a feature behind or beyond a feature flag
- Consolidating duplicate implementations
- Planning how a new system will be retired later (design-time deprecation path)
When not to use (use instead)
- Framework/package version upgrades with no product sunset — pn-migration-planning
- Emergency rollback of a bad deploy — ops runbooks / pn-ship-checklist
Principles
- Code is a liability — removal reduces maintenance and security surface when behavior is truly obsolete.
- Hyrum's Law — users depend on observable behavior, including bugs; migrations must be active, not only announcements.
- Deprecation starts at design — narrow surfaces, explicit contracts, and flags make later removal cheaper.
Process
- Inventory consumers — internal callers, external clients, docs, analytics events; search repo and (if applicable) partner docs.
- Classify deprecation
- Advisory: documented + telemetry; old path still works for a window.
- Compulsory: hard deadline, breaking after date; migration tooling or codemods where possible.
- Publish path — migration guide, dual-write/dual-read period if needed, feature flag stages.
- Measure — know remaining usage before flipping removal; define success metrics.
- Remove — delete code, tests, flags, and docs together; avoid zombie branches and half-dead toggles.
- Verify — tests, integration, and (if external API) consumer communication or version policy check.
Rationalizations
| Excuse | Reality |
|---|---|
| "We'll document it and users will migrate." | Without enforcement and tooling, Hyrum's Law wins. |
| "Leave the old API forever as alias." | Aliases accumulate debt; set an end date. |
| "We'll delete the flag later." | Zombie flags rot; delete in the same release train when safe. |
| "Nobody uses it." | Prove with search, logs, or dependency data. |
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 First seen · 71 lines · 60 tokens per session scan A acfcd06d8ad9
pn-deprecation-and-removal is a skill published in the GitHub repository perniemann/pnCore (0 stars, last pushed 3d ago), licensed MIT. It adds 60 tokens to every session and 746 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 2026-09-03.
Other skills, from other repositories
skill-author
Package and validate an existing skill draft for AutoVault when its frontmatter, resources, capabilities, or admission result need review.
otto-impact-assessment
Check the final diff's consumers, focused tests, evidence, and gaps.
feature-publish
Commit the feature, write the PR body, publish in the selected mode, and drive the PR.
otto-review-remediation
Handle trusted reviewers' change requests on Otto PRs.
cocoreview
CocoReview — structured code review with six-severity findings vocabulary, progressive disclosure architecture, and universal anti-pattern baseline. Invoked via $review [file] [--complexity] [--security] [--architecture] [--language ].
factory-rereview
Re-review a pull request after a push — reconcile the previous review against the new commits, look for new defects the push introduced, then a fresh pass over the whole PR, and finish with a verdict on the PR.