chore(pre-commit): format .NET code via a local dotnet-format hook

[devantler]

🤖 Generated by the Daily AI Assistant

Problem

.pre-commit-config.yaml shipped empty (repos: []) while both its header comment and AGENTS.md promised "automatic .NET code formatting" — a no-op that delivers nothing. It also diverges from its sibling go-template, which ships a working config (golangci-lint-fmt + a local hook). This is the pre-commit watch-item flagged in the roadmap epic #167 ("either populate with a useful hook (e.g. dotnet format) or drop it").

Change

Wire up the .NET equivalent of go-template's setup — a local dotnet-format hook (mirroring go-template's local-hook pattern) that runs dotnet format on staged C# changes:

repos:
  - repo: local
    hooks:
      - id: dotnet-format
        name: Format .NET code with dotnet format
        entry: dotnet format
        language: system
        files: '\\.cs$'
        pass_filenames: false

Adopters opt in with pre-commit install and get format-on-commit that matches the template's EnforceCodeStyleInBuild / TreatWarningsAsErrors stance — catching formatting locally before it becomes a CI build error. AGENTS.md updated to describe the configured hook (was "empty/prepared … no hooks configured yet").

Real finding the hook surfaced

Running the new hook revealed pre-existing drift the in-build analyzers miss: both example .cs files carried a UTF-8 BOM (EF BB BF), violating the repo's own .editorconfig charset = utf-8 rule (charset/BOM normalization is a dotnet format concern, not a build-enforced analyzer rule, so it slipped past CI). Stripped the BOM so the scaffold is dotnet format-clean and the hook passes on first run for adopters.

Validation (local, .NET 10.0.300 SDK)

• pre-commit validate-config ✅ · yamllint ✅ (only the cosmetic document-start warning, matching the original file and go-template's config)
• pre-commit run dotnet-format --all-files → Failed once (fixed the BOM drift), then Passed clean (idempotent) ✅
• dotnet build -c Release → 0 warnings, 0 errors ✅ · dotnet test -c Release → 2 passed ✅

Notes

• Dev-convenience tooling only — no CI/build/release behaviour change; chore: so it does not cut a NuGet release.
• One coherent concern: the BOM fix is a prerequisite for the hook to pass out-of-box, not a mixed-in refactor.

[github-code-quality]

Code Coverage Overview

Languages: C#

C# / code-coverage/dotnet

The overall coverage in the claude/precommit-dot... branch is 100%. Coverage data for the main branch is not yet available.

Show a code coverage summary of the most covered files.

File	main	claude/precommit-dot... 401a7de	+/-
/home/runner/wo...ExampleClass.cs	—	100%	—

---

_{Code Coverage is in Public Preview. Learn more and provide us with your feedback.}

[Copilot]

Pull request overview

Wires up the previously-empty .pre-commit-config.yaml with a local dotnet-format hook that runs dotnet format on staged C# changes, removes pre-existing UTF-8 BOMs from the two example .cs files (which violated .editorconfig's charset = utf-8), and updates AGENTS.md to describe the now-configured hook.

Changes:

• Add a local dotnet-format pre-commit hook triggered by *.cs changes.
• Strip UTF-8 BOM from ExampleClass.cs and ExampleClassTests.cs.
• Update AGENTS.md to reflect the configured hook (replacing the prior "no hooks configured yet" wording).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
.pre-commit-config.yaml	Replaces empty repos: [] with a local dotnet format hook scoped to *.cs.
src/Example/ExampleClass.cs	Removes leading UTF-8 BOM.
tests/Example.Tests/ExampleClassTests.cs	Removes leading UTF-8 BOM.
AGENTS.md	Updates description of .pre-commit-config.yaml to mention the new hook and opt-in via pre-commit install.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.