100-go-rules

100 Go Rules

Use this skill as a compact rule engine, not as a book to read end-to-end.

Selection and operating baseline

• Select this global reference for material Go-language or quality decisions. It complements a specialist skill when needed; specialists do not invoke it mechanically.
• Locate the target module's go.mod before applying version-dependent guidance. Use its go directive for language semantics when present.
• When no target module or go directive is available, use Go 1.26 as the fallback baseline. Do not describe that fallback as a discovered project version.
• Treat user-specified version constraints as authoritative.
• Read references/version-notes-go1.26.md when a finding touches version-sensitive behavior or the project targets a version other than 1.26.
• Prefer current Go semantics, compiler/runtime evidence, and standard-library behavior over historical advice.

Progressive disclosure

Load the smallest domain file that covers the task. Each numbered rule is self-contained and keeps its explanation and Bad/Better examples together, so never search for a second examples file.

Rules	Domain	Reference
1-16	Code/project	references/01-code-project.md
17-29	Data types	references/02-data-types.md
30-35	Control structures	references/03-control-structures.md
36-41	Strings	references/04-strings.md
42-47	Functions/methods	references/05-functions-methods.md
48-54	Errors	references/06-errors.md
55-60	Concurrency foundations	references/07-concurrency-foundations.md
61-74	Concurrency practice	references/08-concurrency-practice.md
75-81	Standard library	references/09-standard-library.md
82-90	Testing	references/10-testing.md
91-100	Optimization/runtime	references/11-optimization-runtime.md

Follow these loading rules:

1. For a normal task, load one domain file; load at most three when the code genuinely spans domains.
2. For a specific rule number, load only its domain file and focus on that rule's section.
3. For a code review, use the colocated examples only as diagnostic/remediation aids; do not mechanically copy them into the response.
4. For a full audit against all 100 rules, evaluate domain files sequentially rather than preloading all eleven.
5. Read references/version-notes-go1.26.md only for version-sensitive findings or compatibility analysis.

Execution and completion

1. Determine the effective Go version and select only the applicable domain reference(s).
2. Apply the relevant rules to the concrete code or design decision; validate claims against local code and use focused tests, benchmarks, compiler, or runtime evidence when available.
3. Report the effective version (and whether it was discovered or a fallback), loaded domain(s), material guidance, and validation evidence. State when no validation command was available.

Applying rules

• Treat each rule as a diagnostic heuristic, not an unconditional law.
• Prioritize correctness and resource safety, then API clarity/maintainability, then performance.
• Validate a suspected issue against actual code context before reporting it.
• Do not report a rule merely because its keyword appears.
• Do not recommend speculative abstractions or micro-optimizations without evidence.
• For performance findings, use or request benchmarks/profiles when the claim depends on workload behavior.
• When rules conflict, preserve correctness and choose the simplest API for demonstrated requirements.
• Treat each Bad/Better pair as an illustration, not a mechanical rewrite template. Adapt names, ownership, errors, concurrency, and lifecycle to the actual code.

Code review output

For each material finding, provide:

• severity: bug, risk, maintainability, or performance
• location or code fragment
• rule number and short title
• concise explanation tied to the concrete code
• smallest practical fix
• a compact before/after snippet when it materially clarifies the fix
• version note only when behavior differs across Go versions

Avoid dumping unrelated rules. If no relevant violation is found, say so.

Code generation and refactoring

Apply relevant rules silently while producing code. Mention rule numbers only when they explain a non-obvious design choice, tradeoff, or compatibility constraint.

Source and adaptation policy

The numbered taxonomy and titles originate from Teiva Harsanyi's 100 Go Mistakes and How to Avoid Them / 100go.co. Rule explanations and code snippets in this skill are compact adaptations written for this skill, updated for Go 1.26, and are not intended as verbatim copies of the site's prose or examples. Preserve this attribution if redistributing or substantially extending the corpus.