How do I install the Fsharp Diagnostics skill?

Run npx skillmds@latest add dotnet/fsharp-diagnostics in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Fsharp Diagnostics safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Fsharp Diagnostics?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Fsharp Diagnostics free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Fsharp Diagnostics?

.NET (Microsoft) (@dotnet) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Fsharp Diagnostics by dotnet — Agent Skill

Name: Fsharp Diagnostics
Author: .NET (Microsoft)

Fsharp Diagnostics

Always invoke after editing `.fs` files under `src/Compiler/`. Fast parse/typecheck without `dotnet build`, plus symbol references and inferred type hints. Use whenever the user asks about F# errors, compile errors, type inference, finding usages, or renaming a symbol in the compiler tree.

.NET (Microsoft) 51afcdb 9 files · 37.9 KB Updated Sep 17, 2026 4k repo stars

File contents

F# Diagnostics

Scope: src/Compiler/ files only.

Setup (once per session)

Requires pwsh 7+ (brew install powershell / winget install Microsoft.PowerShell / apt install powershell).

function GetErrors { & "$(git rev-parse --show-toplevel)/.github/skills/fsharp-diagnostics/scripts/get-fsharp-errors.ps1" @args }

From bash/zsh without a function: pwsh -File <repo>/.github/skills/fsharp-diagnostics/scripts/get-fsharp-errors.ps1 <args>.

Parse first, typecheck second

GetErrors -ParseOnly src/Compiler/Checking/CheckBasics.fs   # syntax only
GetErrors            src/Compiler/Checking/CheckBasics.fs   # full typecheck

Fix all parse errors before typechecking; type errors on top of bad syntax are noise.

Symbol references (line 1-based, col 0-based)

GetErrors -FindRefs src/Compiler/Checking/CheckBasics.fs 30 5

Use before any rename.

Type hints (line range, 1-based)

Returns the range with inferred types as inline // (name: Type) comments:

GetErrors -TypeHints src/Compiler/TypedTree/TypedTreeOps.Transforms.fs 100 120

Other

GetErrors -CheckProject   # typecheck entire project
GetErrors -Ping           # liveness check, no side effects
GetErrors -Shutdown

Timing

First real call after a fresh clone: server build + in-memory warmup, 5–15 min → initial_wait=1200.
After warmup: real commands answer in seconds → initial_wait=180.
-Ping / -Shutdown: sub-second; never trigger build or warmup.

Auto-shuts down after 4h idle; ~3 GB RAM while running.

Frequently asked questions