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 shennawardana23/skillme --skill deprecation-and-migrationgit clone --depth 1 https://github.com/shennawardana23/skillmeWrote 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/shennawardana23/skillme/deprecation-and-migration)<a href="https://agentmods.dev/skills/shennawardana23/skillme/deprecation-and-migration"><img src="https://agentmods.dev/badge/skills/shennawardana23/skillme/deprecation-and-migration/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/shennawardana23/skillme/deprecation-and-migration"><img src="https://agentmods.dev/badge/skills/shennawardana23/skillme/deprecation-and-migration.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 | $0.00069 | $0.01783 |
| Opus 5 | $0.00034 | $0.00892 |
| Sonnet 5 | $0.00014 | $0.00357 |
| Haiku 4.5 | $0.00007 | $0.00178 |
Grade A, and why
deprecation-and-migration 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 — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Deprecation and Migration
Code is a liability, not an asset: every line has an ongoing cost in tests, dependency updates, security patches, and onboarding overhead. Deprecation is the discipline of removing code that no longer earns that cost back. Most organizations are good at building; few are good at removing — this skill is about the removing half.
The deprecation decision
Answer these in order before deprecating anything:
- Does it still provide unique value? If yes, maintain it; stop here.
- How many consumers depend on it? Quantify with actual usage data (call metrics, import graph, dependency scan) — not a guess.
- Does a working replacement exist? If not, build and prove the replacement in production first. Never deprecate without an alternative already available.
- What's the per-consumer migration cost? Trivially automatable
(codemod,
go fix-style rewrite) vs. manual and high-effort changes the decision. - What's the cost of not deprecating? Security exposure, engineer time maintaining it, complexity tax on everything nearby.
Compulsory vs. advisory
| Type | When | Mechanism |
|---|---|---|
| Advisory (default) | Old system is stable; migration optional | // Deprecated: comments, linter warnings, docs. Consumers migrate on their own schedule. |
| Compulsory | Security issue, unsustainable maintenance cost, or the old system blocks other work | Hard removal date, migration tooling provided, active tracking of remaining consumers |
Compulsory deprecation without migration tooling is just an announcement that ships the work onto consumers — that's the "Churn Rule": whoever owns the thing being deprecated owns migrating its users, or ships a backward-compatible replacement that needs no migration at all.
Go-specific mechanics
Mark deprecated exported identifiers with the standard doc-comment
convention go vet and IDEs recognize — this makes the deprecation
visible at every call site, not just in documentation nobody reads:
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 · 175 lines · 69 tokens per session scan A 7b36645b1e96
deprecation-and-migration is a skill published in the GitHub repository shennawardana23/skillme (2 stars, last pushed 15d ago), licensed Apache-2.0. It adds 69 tokens to every session and 1,783 once invoked, about $0.0003 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 2026-08-31.
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