Interactive markdown in MeshWeaver is backed by a Roslyn scripting kernel (Microsoft.CodeAnalysis.CSharp.Scripting). It supports the same package-management directive Polyglot Notebooks made familiar: #r "nuget:PackageId, Version" — but the implementation is MeshWeaver's own, not .NET Interactive's. MeshWeaver resolves the package in-process using NuGet.Protocol, NuGet.Packaging, and NuGet.Resolver — no .NET SDK, no MSBuild — adds its assemblies to the kernel's compilation references, and the package is usable immediately without restarting the portal.

Basic usage

Place one or more #r "nuget:..." directives at the top of a code cell, then write code that depends on them:

#r "nuget:Humanizer, 2.14.1"
using Humanizer;
"hello_world_framework".Humanize()

When MeshWeaver renders a cell like this, it:

1. Submits the entire cell to the kernel as a single SubmitCodeRequest.
2. NuGetDirectiveParser.Extract strips the #r "nuget" directives from the source, and INuGetAssemblyResolver.ResolveAsync calls api.nuget.org and restores the package and its transitive dependencies into the local NuGet cache.
3. Adds every resolved assembly to the kernel's script options (scriptOptions.AddReferences(...)) and installs a runtime probe for the package's probing directories.
4. Compiles and runs the remaining code against the augmented reference set.

The return value is rendered into the --render area. NuGet resolution pipeline: the #r directive triggers an in-process restore; resolved assemblies are added to the kernel's references before the remaining code compiles and runs.

Pinning versions

Always pin a specific version. Omitting the version resolves "latest" at render time, making articles non-reproducible and risking silent breaking changes.

#r "nuget:Humanizer, 2.14.1"   // good — reproducible
#r "nuget:Humanizer"             // avoid — resolves latest at render

Multiple packages

List one directive per line. Order does not matter — all directives in the cell are resolved before any code runs:

#r "nuget:Humanizer, 2.14.1"
#r "nuget:Markdig, 0.37.0"
using Humanizer;
using Markdig;
var heading = "hello_world".Humanize(LetterCasing.Title);
Markdown.ToHtml($"# {heading}\n\nGenerated.")

Sharing packages across cells

Once a package is resolved in any cell of an article, it stays available for every later cell in the same kernel session. You only need the using statement — the #r directive is not required again:

#r "nuget:Humanizer, 2.14.1"
using Humanizer;
"first_cell".Humanize()

// Humanizer is already loaded from the cell above — no #r needed.
using Humanizer;
DateTime.UtcNow.AddMinutes(-5).Humanize()

What happens on failure

If the package ID is unknown, the version does not exist, or the kernel cannot reach nuget.org, the restore throws and the cell fails. The error is rendered inline — the author sees exactly what went wrong without tailing server logs:

#r "nuget:ThisPackageDoesNotExist, 1.0.0"
"unreachable"

Also in node types

The same #r "nuget:..." directive works at the top of any Source/*.cs file in a node type. See NuGet Packages in Node Types for the end-to-end walkthrough.

Deployment — no SDK required

The restore is a pure library operation. It does not shell out to dotnet restore and does not require MSBuild, so the ACA image stays as the lean mcr.microsoft.com/dotnet/aspnet runtime. The two requirements are:

Related

• Interactive Markdown — how code cells and --render areas work
• NuGet Packages in Node Types — same directive inside Source/*.cs files
• Data Modeling — referencing your own schema types from a code cell