Maintain classic ASP.NET applications on .NET Framework, including Web Forms, older MVC, and legacy hosting patterns, while planning realistic modernization boundaries. USE FOR: working in Web Forms, legacy MVC, or classic ASP.NET applications; reviewing old IIS-centric configuration and lifecycle behavior; planning migration toward ASP.NET Core. DO NOT USE FOR: unrelated stacks; generic tasks that do not need this specific guidance. INVOKES: inspect the repository context, edit targeted files,
NewMaintained
Automatic
◆Coding pack
Last verified 8/19/2026
What it changes
Passed 0 of 22 test cases with the skill, and 22 of 22 without it.
Without skill100%
With skill0%
0 fixed20 passed either way1 still failing1 broke
Pass-rate lift
-100 pp
Tokens
+5%
Agent turns
0%
Response time
-9%
Model gemini-3.6-flashMeasured 8/19/2026v120 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
What's inside
The instructions your model reads when the skill loads.
SKILL.md33 lines3 files
Legacy ASP.NET
Trigger On
working in Web Forms, legacy MVC, or classic ASP.NET applications
reviewing old IIS-centric configuration and lifecycle behavior
planning migration toward ASP.NET Core without breaking core business flows
Workflow
Treat classic ASP.NET as a distinct stack with different hosting, lifecycle, and configuration rules from ASP.NET Core.
Stabilize behavior first: routing, session, auth, server controls, configuration transforms, and deployment assumptions.
Plan modernization in seams: isolate domain and service logic, then move replaceable edges instead of rewriting the whole app at once.
Use wcf or entity-framework6 when the legacy app depends on those subsystems rather than flattening them into generic web work.
Be careful with guidance copied from ASP.NET Core because middleware, DI, and hosting assumptions do not transfer directly.
Validate in an environment that resembles real IIS and configuration transforms.
Deliver
practical maintenance guidance for classic ASP.NET
stabilized legacy behavior and modernization seams
a migration path that avoids unnecessary risk
Validate
classic and Core guidance are not mixed
legacy runtime assumptions are preserved deliberately
migration steps are incremental and testable
References
Migration Paths: strategies for migrating from ASP.NET to ASP.NET Core, including incremental migration, strangler fig pattern, and component-specific guidance
Maintenance Patterns: stabilization and maintenance patterns for legacy ASP.NET code, including abstraction layers, testing seams, and deployment practices
Use ManagedCode.MarkItDown when a .NET application needs deterministic document-to-Markdown conversion for ingestion, indexing, summarization, or content-processing workflows. USE FOR: ManagedCode.MarkItDown integration; document ingestion flows; Office or rich-text conversion to Markdown; indexing and summarization pipelines. DO NOT USE FOR: unrelated stacks; generic tasks that do not need this specific guidance. INVOKES: inspect the repository context, edit targeted files, and run relevant bui