We split this copilot-instructions.md into the rules it gives an agent

17 rules. About 1 is common, 11 are distinctive, and 5 are very specific to this project.

• ≈1

  Common · estimate

  Many files like this have a rule of this kind.

• ≈11

  Distinctive · estimate

  This author's own choices. Worth a look.

• 5

  Very specific

  Tied to their project's names, files or tools. Probably skip.

• Common
• Distinctive
• Very specific

1. Distinctive:

   Use these make commands:

   line 6
2. Very specific:

   Test with coverage: make test-coverage

   line 9
3. Very specific:

   Check all: make check (runs fmt, vet, lint, and test)

   line 14
4. Very specific:

   When adding a new dependency, use go get <package> and run make deps to tidy.

   line 16
5. Distinctive:

   Keep the dependency list minimal and prefer well-maintained packages.

   line 17
6. Distinctive:

   Follow Go conventions and idiomatic patterns

   line 21
7. Common:

   Use proper error handling (never ignore errors)

   line 22
8. Distinctive:

   Follow the standard Go project layout

   line 23
9. Very specific:

   Use gofmt for formatting (enforced by make fmt)

   line 24
10. Distinctive:

    Keep business logic out of HTTP handlers

    line 29
11. Distinctive:

    Use interfaces for abstractions

    line 30
12. Distinctive:

    Use Go's built-in testing framework

    line 33
13. Distinctive:

    Add unit tests for all new functions

    line 34
14. Very specific:

    Run tests with race detector: make test

    line 36
15. Distinctive:

    Use table-driven tests where appropriate

    line 37
16. Distinctive:

    Write clear package documentation

    line 41
17. Distinctive:

    Document exported functions and types

    line 42

≈ “Common” is an estimate: at least 1 in 5 of the 3,669 Copilot instructions files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

• Where files are headingNew Copilot instructions files have more rules about branches and pull requests, and fewer about code style.

  Of the Copilot instructions files we read, the 2,297 first seen in the last six months, against the older ones: the kind of rule that gained most share, and the kind that lost most. About files like this in general, not this one, and an estimate, since a kind is a pattern in the words.