Provide `Language Model Tools` for LLM/VS Code Agent to Manage .NET by nagilson · Pull Request #2557 · dotnet/vscode-dotnet-runtime

nagilson · 2026-02-06T18:56:44Z

Add Language Model Tools for AI Agent Integration in VS Code

Summary

This PR adds Language Model Tools (languageModelTools) support to the .NET Install Tool extension, enabling AI agents like GitHub Copilot to help users manage .NET installations through natural language interactions.

This is an improvement upon #2375 (inspired by a convo with Rich) - at the time of that PR, agents couldn't directly invoke vscode contributing commands, so this approach used an MCP server and a subprocess that could communicate with the MCP server. Now there's a more robust way of doing this.

I also messed around with the agent window and setting up repos myself before adding this. The agent seemed to get very confused on what the existingPath setting did amongst other things, and it didn't understand how the dotnet hive / muxer worked and what installs were available where, and how they were used. I was somewhat inspired by a 'dogfooding' effort we did to try to use our own tooling. I've improved its knowledge of .NET now.

Changes

New Features

Language Model Tools (7 tools)

Added support for VS Code's languageModelTools contribution point.
See https://code.visualstudio.com/api/extension-guides/ai/tools

Most Important Files

vscode-dotnet-runtime-extension/package.json <-- (defines tools)
vscode-dotnet-runtime-extension/src/LanguageModelTools.ts <-- implements tools
vscode-dotnet-runtime-extension/src/SettingsInfoContent.ts

Tools added:
install_dotnet_sdk
list_available_dotnet_versions_to_install
find_dotnet_executable_path
uninstall_dotnet
get_settings_info_for_dotnet_installation_management
list_installed_dotnet_versions
get_recommended_sdk_version

Tested

I made sure that running vscode unelevated didn't confuse the llm when the tools require an admin prompt dialog box to continue.
I tested failure modes to see if the AI agent can properly recover using our errors (obviously hard to do for every error, which I did not)
I tested unsupported scenarios to make sure we don't make the llm worse for unsupported scenarios and instead guide it in the right direction
Before and after versions - before it would run several commands to check the machine state and require user permission, when the data was already available via our extension without requiring permission. The agent also preferred winget in the past even for admin installs of the SDK but it now prefers admin installed SDKs and local runtimes as that is what the extension supports. This is intentional.
Trying to manage out of support versions / global.json pinned versions - it took tweaking for the llm to not be annoying/reject requests/use latest instead.

Example:
📦 It can install SDK / Find Installs

Before:
https://github.com/user-attachments/assets/5f45102a-77da-40a4-ba04-0229ace06748%20%20

Agent has to wait for 2 separate commands + approval to run from the user (tedious and disrupts workflow) to get info it already has
Now:
https://github.com/user-attachments/assets/781b2318-2515-4bad-b1e5-84b0cdce0ba7%20
https://github.com/user-attachments/assets/cb6c7fb8-b1f6-43ff-870b-1cae71441258
The agent is more consistently aware (from my anecdotal testing) of what installs the user might need and informs the user. This happened sometimes for me prior but not always, as shown in the ss above.

🐧 Linux PPA

Before the LLM always used install scripts with claude opus 4.5, 4.6, chat codex 5. Sometimes this hit pathing issues.
Now it correctly follows our guidance, and tries to run the commands to either set up backport PPA or use the official feeds:

🗺️ Global.Json Paths Feature

If the user tries to use their own custom SDK it helps point them to the new 'paths' feature in global.json.

⚠️ Errors Propagate

This text shows the LLM is able to receive the errors we return and move forward/provide guidance.

--

These can be disabled in the extension settings of the .NET Install Tool:

Guidance

I followed the best practices as outlined by Anthropic to write these tools.
https://platform.claude.com/docs/en/agents-and-tools/agent-skills/best-practices
https://resources.anthropic.com/hubfs/The-Complete-Guide-to-Building-Skill-for-Claude.pdf
https://code.claude.com/docs/en/memory#write-effective-instructions

…nstall # Add Language Model Tools for AI Agent Integration ## Summary This PR adds Language Model Tools (`languageModelTools`) support to the .NET Install Tool extension, enabling AI agents like GitHub Copilot to help users manage .NET installations through natural language interactions. This is an improvement upon dotnet#2375 - at the time of that PR, agents couldn't directly invoke vscode contributing commands, so this approach used an MCP server and a subprocess that could communicate with the MCP server. Now there's a more robust way of doing this. ## Changes ### New Features #### Language Model Tools (6 tools) Added support for VS Code's `languageModelTools` contribution point with the following tools: | Tool | Purpose | |------|---------| | `installDotNetSdk` | Install .NET SDK system-wide (MSI on Windows, PKG on macOS, apt/yum on Linux) | | `listDotNetVersions` | List available .NET SDK/Runtime versions from Microsoft with support phase info | | `listInstalledDotNetVersions` | Query installed SDKs/Runtimes for a given dotnet executable | | `findDotNetPath` | Find existing .NET installations that meet version/architecture requirements | | `uninstallDotNet` | Uninstall .NET SDK or Runtime versions | | `getDotNetSettingsInfo` | Comprehensive guide about settings, installation types, and troubleshooting | Each tool includes: - Detailed `modelDescription` with OS-specific guidance (MSI/PKG/apt/yum installers) - User-friendly `userDescription` - JSON schema for parameters - Comprehensive error handling with troubleshooting tips #### Comprehensive AI Agent Documentation The `getDotNetSettingsInfo` tool returns a detailed guide covering: - Difference between LOCAL (extension-managed) vs GLOBAL (system-wide) installs - `existingDotnetPath` setting explanation (commonly misunderstood) - SDK vs Runtime versioning relationship - `global.json` file handling - Common user scenarios and troubleshooting - "Uninstall trick" for registering global SDKs not in the extension's list

its hard to verify since it involves installing / uninstalling from the system state and requires user interaction. This may be overkill and im open to removing some of this.

This allows the extension to run properly on the new version of code + node js + ts that supports llm features

…activation

… llm worse for these

…stalling

…reporting

only 1xx versions are supported by the built in ppa feeds.

We should fix this, I'm not going to do it here or now. I think this was added here to make a minimal diff at the time.

this made it invalid json

…x if major or major.minor only format provided

.split returns 1 no matter what so the 0 condition was wrong.

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

…lson/vscode-dotnet-runtime into nagilson-mcp-for-installing

Copilot

Pull request overview

Copilot reviewed 23 out of 27 changed files in this pull request and generated 5 comments.

… is supported

Copilot

Pull request overview

Copilot reviewed 26 out of 30 changed files in this pull request and generated 3 comments.

… always trim

these are the only bifurcations that are truly supported.

…find Path

…ailable installs' on

…k managed path

Copilot

Pull request overview

Copilot reviewed 34 out of 38 changed files in this pull request and generated 2 comments.

+import * as os from 'os';
 import * as path from 'path';
+import { IEventStream } from '../EventStream/EventStream';
 import


+        "languageModelTools": [
+            {
+                "name": "install_dotnet_sdk",
+                "when": "config.dotnetAcquisitionExtension.enableLanguageModelTools",
+                "displayName": "Install .NET SDK",
+                "toolReferenceName": "installDotNetSdk",
+                "canBeReferencedInPrompt": true,
+                "icon": "$(tools)",
+                "userDescription": "Installs a .NET SDK system-wide for building and running .NET projects",


nagilson added 22 commits February 6, 2026 10:54

add more tests

ee1e5f6

its hard to verify since it involves installing / uninstalling from the system state and requires user interaction. This may be overkill and im open to removing some of this.

enable faster query of .net installs

2fa2f73

proper node version for VS Code version

c564427

bump ts version and dependencies

f111e7e

This allows the extension to run properly on the new version of code + node js + ts that supports llm features

fix typescript / node version dependencies for new vscode vers

45460e1

lint + unspported scenarios

d2363a4

Logging of language model tool consumption + tests prevent duplicate …

67a9746

…activation

add can be referenced in prompt, shorten model description

6ca8651

language model tool specifications follow guidance

09e9589

Warn of unsupported scenarios + link to proper reference - don't make…

8d4b0a8

… llm worse for these

add ability to throw back up error for better llm diagnostic

960b546

Merge remote-tracking branch 'upstream/main' into nagilson-mcp-for-in…

329f181

…stalling

cautious creation of worker context for uninstall cmd failure error …

d1145e5

…reporting

merge fix

3740d6f

dont truncate what is available.

76925b5

missing code rmvl

03412fc

group runtimes properly

69763d3

group runtimes properly

4b005d8

fix tests and unix pool

73ccf5b

pool provider fix

854c9ad

use paths feature in global json for local sdk

e35a97a

nagilson requested a review from a team February 13, 2026 20:47

MiYanni approved these changes Feb 14, 2026

View reviewed changes

Comment thread 1pr-azure-pipeline.yml Outdated

Comment thread vscode-dotnet-runtime-extension/src/LanguageModelTools.ts Outdated

nagilson added 6 commits February 17, 2026 10:08

Fix pool provider again

9cb2d2f

Move instrutions to a new file

abbd462

Try to improve unsupported scenario and error handling

b50da38

Use Test Versions to match CI Runner version support

051d729

allow disabling the LLM tools

a6ee7f9

try to include needed unix dependency for new image

d81721d

nagilson and others added 6 commits June 8, 2026 13:17

provide a supported linux version when the input version is vague

d2f08e6

only 1xx versions are supported by the built in ppa feeds.

add note about better coding pattern for version compare

6f7ce7d

We should fix this, I'm not going to do it here or now. I think this was added here to make a minimal diff at the time.

remove trailing comma from json

f9b7cde

this made it invalid json

add tests for linux patch using latest gap + test for linux using .1x…

954b205

…x if major or major.minor only format provided

Fix getMajorMinor implementation

aea2fa0

.split returns 1 no matter what so the 0 condition was wrong.

Fix distro support message to LLM

5cf4fc1

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings June 8, 2026 20:38

Copilot started reviewing on behalf of nagilson June 8, 2026 20:38 View session

Merge branch 'nagilson-mcp-for-installing' of https://github.com/nagi…

f1b26df

…lson/vscode-dotnet-runtime into nagilson-mcp-for-installing

Copilot AI reviewed Jun 8, 2026

View reviewed changes

nagilson added 5 commits June 8, 2026 13:47

Fix string formatting on settings info content for llm

cf4ff90

Move uninstall failure into the error helper

f2c0494

deduplicate code for formatting text responses to the llm

4c1d3c8

nit: whitespace fix

b26ddcb

linting nit: use stronger type checking on tool options now that this…

c7e07ab

… is supported

Copilot AI review requested due to automatic review settings June 8, 2026 21:11

Copilot started reviewing on behalf of nagilson June 8, 2026 21:11 View session

Copilot AI reviewed Jun 8, 2026

View reviewed changes

Comment thread vscode-dotnet-runtime-library/src/Utils/TypescriptUtilities.ts Outdated

Comment thread vscode-dotnet-runtime-extension/src/test/functional/index.ts

Comment thread vscode-dotnet-runtime-extension/package.json

nagilson added 9 commits June 8, 2026 14:22

Replace , with . in documented url

6afbaed

Fix parsing for os-release to consider # in the file as a comment and…

fbdb699

… always trim

split uninstall commands into global sdk and local runtime

25e0763

these are the only bifurcations that are truly supported.

separate out uninstall tools into 2 separate tools + prepare to call …

39cb03a

…find Path

use path.dirname to set the path to the directory holding the executable

6617409

fix merge with acquire result check

1d9129a

do not allow runtime admin installation as it will have a bad version

6451111

Add option to fallback to findPath to find a muxer to run to 'find av…

268950b

…ailable installs' on

Add method to determine if the path 'is a' vscode local runtime or sd…

e0e466c

…k managed path

Copilot AI review requested due to automatic review settings June 8, 2026 23:24

Copilot started reviewing on behalf of nagilson June 8, 2026 23:24 View session

Copilot AI reviewed Jun 8, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Provide `Language Model Tools` for LLM/VS Code Agent to Manage .NET#2557

Provide `Language Model Tools` for LLM/VS Code Agent to Manage .NET#2557
nagilson wants to merge 91 commits into
dotnet:mainfrom
nagilson:nagilson-mcp-for-installing

nagilson commented Feb 6, 2026 •

edited

Loading

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

Conversation

nagilson commented Feb 6, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Add Language Model Tools for AI Agent Integration in VS Code

Summary

Changes

New Features

Language Model Tools (7 tools)

Most Important Files

Tested

Guidance

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

nagilson commented Feb 6, 2026 •

edited

Loading