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 eduardo-sl/go-agent-skills --skill go-modernizegit clone --depth 1 https://github.com/eduardo-sl/go-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/eduardo-sl/go-agent-skills/go-modernize)<a href="https://agentmods.dev/skills/eduardo-sl/go-agent-skills/go-modernize"><img src="https://agentmods.dev/badge/skills/eduardo-sl/go-agent-skills/go-modernize/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/eduardo-sl/go-agent-skills/go-modernize"><img src="https://agentmods.dev/badge/skills/eduardo-sl/go-agent-skills/go-modernize.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 | $0.00126 | $0.02450 |
| Opus 5 | $0.00063 | $0.01225 |
| Sonnet 5 | $0.00025 | $0.00490 |
| Haiku 4.5 | $0.00013 | $0.00245 |
Grade A, and why
go-modernize 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 11d 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 — 246 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Go Modernize
Go evolves. Code written for Go 1.16 should not look the same as code targeting
Go 1.25+. Modernize incrementally — update go.mod, then adopt new patterns.
Never adopt a feature above the go directive in go.mod. Raise the
directive deliberately, in its own commit, and only to a version the project's
CI and deployment images actually run.
Detailed reference material, loaded on demand:
references/generics.md— replacinginterface{}with type parameters, constraints, generic containers, when NOT to use generics.references/stdlib-migrations.md— before/after examples for slog, errors.Join, slices/maps helpers, range-over-int, and iterators.
Read a reference file only when the summary below is not enough.
Modernization Procedure
-
Check the
godirective ingo.mod— it caps which features you can use. -
Run the official modernizers first — they find and fix the mechanical migrations automatically:
# Go 1.26+ — the modernizers now live in go fix go fix ./... # Go 1.25 and earlier go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...Both rewrite source in place. Commit before running, and review the diff. If neither command is available, apply the table below manually.
-
Scan the table below for the judgment-based migrations the analyzer does not cover (generics, iterators, logger replacement) and apply them case by case.
-
Run
go build ./...and the test suite after each group of changes.
Feature Table by Go Version
| Go Version | Feature | Action |
|---|---|---|
| 1.13+ | errors.Is, errors.As |
Replace == error comparisons |
| 1.13+ | http.NewRequestWithContext |
Replace http.NewRequest |
| 1.16+ | embed |
Replace go-bindata / packr |
| 1.18+ | Generics | Replace interface{} utility functions |
| 1.20+ | errors.Join |
Replace manual error accumulation |
| 1.21+ | log/slog |
Replace log for structured logging |
| 1.21+ | slices, maps |
Replace hand-written slice/map utilities |
| 1.21+ | min, max builtins |
Replace math.Min/math.Max (float64-only) |
| 1.22+ | Range over int | Replace for i := 0; i < n; i++ |
| 1.23+ | Range over func | Replace callback-based iteration |
| 1.23+ | unique.Make |
Replace hand-rolled string interning |
| 1.24+ | for b.Loop() |
Replace for range b.N in benchmarks |
| 1.24+ | t.Context() |
Replace context.Background() in tests |
| 1.24+ | os.Root |
Replace manual path-traversal checks |
| 1.24+ | go.mod tool directive |
Replace the tools.go blank-import file |
| 1.24+ | runtime.AddCleanup |
Replace runtime.SetFinalizer |
| 1.25+ | testing/synctest |
Replace time.Sleep in concurrency tests |
| 1.25+ | sync.WaitGroup.Go |
Replace wg.Add(1) + go func(){defer wg.Done()} |
| 1.26+ | errors.AsType |
Replace errors.As with a declared target variable |
| 1.26+ | slog.NewMultiHandler |
Replace hand-written fan-out handlers |
| 1.26+ | new(expr) |
Replace a temp variable taken by address |
What ships with it
2 files 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.
- 11d ago First seen · 246 lines · 126 tokens per session scan A 682450962ef7
go-modernize is a skill published in the GitHub repository eduardo-sl/go-agent-skills (71 stars, last pushed 24d ago), licensed MIT. It adds 126 tokens to every session and 2,450 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 2026-08-30.
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