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 agentmods add rules/openshift/hypershift/100-go-mistakesgit clone --depth 1 https://github.com/openshift/hypershiftWhat 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 | $0.00000 | $0.00691 |
| Opus 5 | $0.00000 | $0.00345 |
| Sonnet 5 | $0.00000 | $0.00138 |
| Haiku 4.5 | $0.00000 | $0.00069 |
Grade A, and why
100-go-mistakes 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 3d 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 — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
General Best Practices
- Avoid variable shadowing.
- Do not over-nest control flow (e.g., nested
iforforblocks). - Avoid
init()functions unless absolutely necessary. - Keep functions small and focused.
- Prefer composition over inheritance (via embedding).
- Use the functional options pattern for constructors where flexibility is needed.
Interfaces
- Avoid defining interfaces until you need them.
- Do not return interfaces from constructors or public APIs.
- Define interfaces on the consumer side, not the producer side.
- Keep interfaces small and focused (generally 1–2 methods).
Structs and Methods
- Avoid embedding pointer types unless necessary.
- Don’t overuse getters/setters — prefer public fields when it makes sense.
- Use value receivers when the method doesn't mutate state or require pointer semantics.
Packages and Imports
- Do not use
util,common, or similarly vague package names. - Avoid package name collisions by using clear, unique names.
- Do not expose unnecessary symbols (keep exported API minimal).
Slices
- Distinguish between nil and empty slices.
- Avoid memory leaks from slicing large arrays.
- Always check the capacity when copying or appending slices.
- Preallocate slice capacity when size is known ahead of time.
Maps
- Always initialize maps before use.
- Check existence with the two-value assignment (
val, ok := m[key]). - Be aware that ranging over a map is in random order.
Error Handling
- Always check errors — don’t ignore them.
- Wrap errors with context when rethrowing.
- Avoid panics except in truly unrecoverable cases.
- Use
errors.Isanderrors.Asfor error comparison in Go 1.20+.
Goroutines and Concurrency
- Always
defer cancel()when usingcontext.WithCancel. - Do not leak goroutines — ensure they exit cleanly.
- Avoid data races — use mutexes or channels appropriately.
- Never close a channel from the receiving side.
Testing and Debugging
- Name tests consistently:
TestXxx,BenchmarkXxx,ExampleXxx. - Use table-driven tests where possible.
- Avoid global state in tests.
- Use
t.Helper()in helper functions to improve error tracebacks.
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.
- 3d ago First seen · 90 lines · 691 tokens per session scan A c95fa7eea0d7
100-go-mistakes is a cursor rule published in the GitHub repository openshift/hypershift (538 stars, last pushed 3d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 691 tokens. 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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