dotnet-csharpier

Guidance for using CSharpier, an opinionated formatter for C# and XML. An opinionated formatter applies a consistent style with relatively few choices to configure.

In plain words
What is it for?
Use it to choose CSharpier as the main formatter, configure its ignore and project files, and run its check mode in continuous integration.
Why use it?
It helps a .NET team keep formatting consistent without maintaining many style settings, while making ownership clear when other formatters are present.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/managedcode/prompterone/dotnet-csharpier
Any agent
npx skills add managedcode/PrompterOne --skill dotnet-csharpier
Clone the repo
git clone --depth 1 https://github.com/managedcode/PrompterOne

Made for: Claude Code, Codex.

Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 905 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00051 $0.00905
Opus 5 $0.00026 $0.00452
Sonnet 5 $0.00010 $0.00181
Haiku 4.5 $0.00005 $0.00090

Measured yesterday against content hash bbe140a1b07e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

dotnet-csharpier 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 yesterday.

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.

Origin

Copies of this mod

4 near-identical copies found in the catalogue:

.codex/skills/dotnet-csharpier/SKILL.md · 107 lines

How it starts

The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CSharpier for .NET

Trigger On

  • the repo uses or wants CSharpier
  • the team prefers an opinionated formatter over many configurable style knobs

Value

  • produce a concrete project delta: code, docs, config, tests, CI, or review artifact
  • reduce ambiguity through explicit planning, verification, and final validation skills
  • leave reusable project context so future tasks are faster and safer

Do Not Use For

  • repos that already standardized on dotnet format as the only formatter

Inputs

  • the nearest AGENTS.md
  • current formatting ownership model
  • any .csharpierignore or .editorconfig

Quick Start

  1. Read the nearest AGENTS.md and confirm scope and constraints.
  2. Run this skill's Workflow through the Ralph Loop until outcomes are acceptable.
  3. Return the Required Result Format with concrete artifacts and verification evidence.

Workflow

  1. Decide whether CSharpier is the primary formatter or only complements other tools.
  2. Use check mode in CI.
  3. Keep ignore files and config explicit in repo.
  4. Do not let CSharpier and dotnet format both own the same formatting space without documentation.

Bootstrap When Missing

If CSharpier is not configured yet:

  1. Detect current state:
    • rg --files -g '.config/dotnet-tools.json' -g '.csharpierignore'
    • dotnet tool list --local
    • dotnet tool list --global
  2. Prefer local tool installation for reproducible CI:
    • dotnet new tool-manifest (if missing)
    • dotnet tool install csharpier
  3. Add .csharpierignore when needed and define ownership vs dotnet format in AGENTS.md.
  4. Add dotnet csharpier check . to CI.
  5. Run dotnet csharpier check . and return status: configured or status: improved.
  6. If the repo intentionally uses only dotnet format, return status: not_applicable unless migration is requested.

Deliver

  • explicit CSharpier ownership and commands
  • CI-safe formatter checks

Validate

  • formatter ownership is not ambiguous
  • the repo is comfortable with opinionated formatting decisions

Read the full file on GitHub · 107 lines

Files

What ships with it

4 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.

Changes

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.

  1. yesterday First seen · 107 lines · 51 tokens per session scan A bbe140a1b07e

Subscribe to this mod's changes

dotnet-csharpier is a skill published in the GitHub repository managedcode/PrompterOne (42 stars, last pushed 3mo ago), licensed MIT. It adds 51 tokens to every session and 905 once invoked, about $0.0003 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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