PostSharp 2027.0 gives AI coding agents real build data
AI coding agents struggle with PostSharp for a structural reason. The source code of a method shows none of the logging, caching, or thread safety that PostSharp weaves into the compiled assembly. The agent writes aspects from memory, drawing on samples spread across twenty years of PostSharp versions. When the build fails, it deletes the aspect instead of fixing it.
PostSharp 2027.0 addresses all three of those failure modes with four concrete additions.
AI Plugin for Claude Code and Codex
The PostSharp.AI.Skills plugin ships the full documentation in Markdown format, the API reference for every namespace, two search scripts for finding articles and API entries, and compilable source code for all examples. It also instructs the agent to look up the API before writing code, to build and verify, and to fix the root cause of a build message rather than suppressing it.
Install in Claude Code with two commands:
/plugin marketplace add https://github.com/postsharp/PostSharp.AI.Skills
/plugin install postsharpCodex setup is covered in the Configuring AI Coding Agents docs. Available now.
CLI Introspection Without Visual Studio
The new postsharp introspect commands read the files from the last build and report which aspects apply to a given declaration, what created each aspect, and what each one changed and in what order. No IDE required.
postsharp introspect show declaration Orders/Repository.cs:10The JSON output tells the agent that the Log aspect applies to Save because of a multicast attribute on the assembly, which the source of Save does not show. That context is the difference between an agent that fixes the problem and one that deletes the aspect.
The commands are designed for agent consumption: JSON output by default with a stable schema, OData $filter expressions for querying aspect classes and transformations, output capped to fit inside a context window with commands to fetch the rest, a batch mode that runs multiple queries over one project load, and backward compatibility with projects built on PostSharp 2023.0 through 2026.0 on Windows, Linux, and macOS.
Available from 2027.0.7-preview via:
dotnet tool install -g PostSharp.Tool --prereleaseBuild Message Documentation
The new Errors and Warnings reference has one article per message code, such as PS0215, with its cause and the fix. An agent that reads the message code and then its article can repair the code rather than silence the warning. Available from 2027.0.5-preview.
Aspect Test Framework
The PostSharp.Testing.AspectTesting package, built on xunit.v3, is the same framework PostSharp uses to test itself. Each source file is compiled, woven into its own assembly, verified with ILVerify, and run. Tests compare program output and build messages against stored expected files, so a test can assert on a build error. The @CompareTransformedCode annotation decompiles the woven code back to C# and diffs it against a .t.cs snapshot file. Available from 2027.0.5-preview.
These features are in preview and not supported in production. Full release notes are in What’s New in PostSharp 2027.0.
I’m founder of BizStack at Cagri Sarigoz LLC and a passionate advocate for entrepreneurs.
With over 14 years in tech, marketing, and AI, including my role as Head of SEO at CitizenShipper and co-founder of TaleBot at Intale AI, I’m dedicated to sharing genuine, useful product insights and tips.
At BizStack, I aim to cut through the digital noise to provide clear, actionable advice.
And more than all else, I’m a father to a (always) little girl and a husband.
Contact me at [email protected] for assistance.
