In 2026, C# developers leverage Atlas to efficiently upgrade a library to a new major version and repair all resulting compile and test failures. Atlas orchestrates the entire process, from driving `NuGet` for the upgrade to interpreting `dotnet build` output and fixing code, then validating with `xUnit via dotnet test`.
How does Atlas upgrade C# NuGet packages and gather context?
In 2026, upgrading a C# dependency to a new major version with Atlas begins by leveraging `NuGet` through `bash`. Atlas first executes the `NuGet` upgrade command, capturing its full output to understand initial changes. This process ensures that the package manager's actions are fully transparent and recorded.
Atlas initiates the dependency upgrade by running `NuGet` commands via its `bash` tool. For instance, to upgrade a package like `Newtonsoft.Json` in a `.csproj` file, Atlas might execute `dotnet add package Newtonsoft.Json --version <new_major_version>`. The complete output from this `bash` command is captured; if it exceeds terminal limits, Atlas saves it to a file that can be read later using the `read` tool. Following the `NuGet` upgrade, Atlas uses its `webfetch` tool to retrieve the library's release notes or changelog. This crucial step provides the agent with the specific breaking changes and migration guidance directly from the source, ensuring that subsequent fixes align precisely with the library's documented evolution rather than relying on guesswork. This contextual information is vital for Atlas to understand the scope of necessary code modifications within the C# codebase.
How does Atlas identify and fix C# compile errors after a dependency upgrade?
After a C# dependency upgrade, Atlas identifies compile errors by running `dotnet build` through its `bash` tool. This approach, standard for C# developers in 2026, allows the compiler to enumerate all breakage precisely. Atlas then systematically addresses each error, ensuring the codebase becomes clean.
Once a C# dependency is upgraded, Atlas's next step is to identify all compile-time breakage. It achieves this by executing `dotnet build` using the `bash` tool, which is the definitive way to compile C# projects and enumerate errors. Atlas does not predict what might break; instead, it relies on the actual compiler output to provide an exhaustive list of issues. For each reported error, Atlas employs its `edit` tool to modify the C# source files. When a fix requires understanding new method signatures or class structures in the upgraded package, Atlas utilizes the `lsp` tool's `goToDefinition` operation. This allows the agent to inspect the updated API directly within the upgraded `NuGet` package, ensuring that the code modifications are accurate and conform to the new library version. This iterative process of building, identifying errors, and fixing them continues until `dotnet build` reports a clean compilation across the entire C# solution, which might involve files like `Program.cs`, `Startup.cs`, or various `.cs` files within a project.
Validating C# Code with xUnit via dotnet test and dotnet format
In 2026, after fixing C# compile errors, Atlas rigorously validates the codebase using `xUnit via dotnet test` and `dotnet format`. This ensures that not only does the code compile, but all existing tests pass and the code adheres to formatting standards. Atlas repeats this cycle until the solution is fully stable.
After Atlas has addressed all compile errors in the C# codebase, the agent proceeds to validate the integrity and correctness of the changes. This involves running the project's test suite using `xUnit via dotnet test` through the `bash` tool. Passing all tests is a critical indicator that the dependency upgrade and subsequent fixes have not introduced regressions. Atlas will re-run `dotnet build` and `xUnit via dotnet test` iteratively until both operations report success, confirming the stability of the C# application. Furthermore, to maintain code quality and consistency, Atlas can apply `dotnet format` using `bash`. This ensures that all modified C# files, such as `MyService.cs` or `Tests/MyServiceTests.cs`, adhere to the project's formatting standards. Before finalizing any changes, Atlas computes a unified diff for every file edit and surfaces it for approval, allowing the C# developer to review every modification. Atlas also reads `git` branches, status, and diffs, and can stage and create commits on the developer's behalf, providing a comprehensive review and commit workflow.
Atlas's Safety and Review Mechanisms for C# Development
Atlas incorporates multiple safety and review mechanisms for C# projects, ensuring developer control over every change in 2026. Every Atlas tool call is permission-gated, and all proposed code modifications are presented as unified diffs for explicit approval, preventing unintended alterations to `.csproj` or `.cs` files.
Atlas is designed with robust safety and review mechanisms, crucial for C# development in 2026. Before any tool, such as `bash` for `NuGet` or `edit` for C# source files, is executed, Atlas applies permission-gated rules (allow, ask, deny). This means a C# developer always has explicit control over what actions Atlas can take. Furthermore, Atlas drafts a plan in a read-only plan agent and asks for approval before switching to a build agent, providing transparency into its intended workflow. For every modification Atlas proposes to C# files or configuration files like `.csproj` or `.sln`, it computes a unified diff. This diff is then surfaced for the developer's approval, allowing a granular review of every line added, removed, or changed. Atlas also snapshots file changes as `git` patches, enabling easy diffing and rolling back of edits if necessary. This comprehensive review process, combined with Atlas's ability to read `git` status and stage commits, ensures that C# developers maintain full oversight and confidence in the automated dependency upgrade and repair process.
Step by step
- 01Ask Atlas to upgrade a specific `NuGet` package to a new major version using the `bash` tool.
- 02Instruct Atlas to fetch the library's release notes using `webfetch` to understand breaking changes.
- 03Direct Atlas to run `dotnet build` via `bash` to identify all compile-time errors in the C# solution.
- 04Guide Atlas to fix each identified C# error using the `edit` tool, leveraging `lsp.goToDefinition` to inspect new API signatures.
- 05Command Atlas to re-run `dotnet build` and `xUnit via dotnet test` through `bash` until all C# projects compile cleanly and all tests pass.
- 06Ask Atlas to apply `dotnet format` using `bash` to ensure consistent C# code styling.
- 07Review the unified diff of all C# file changes presented by Atlas and approve the modifications.
- 08Instruct Atlas to stage and commit the changes to your `git` repository.
Frequently asked questions
- How does Atlas handle NuGet package upgrades in C#?
- Atlas uses its `bash` tool to execute `NuGet` commands, such as `dotnet add package <PackageName> --version <NewVersion>`, capturing the full output to manage C# dependency upgrades.
- Can Atlas fix C# compile errors from a major version bump?
- Yes, Atlas runs `dotnet build` via `bash` to get actual compiler errors, then uses its `edit` tool and `lsp.goToDefinition` to fix C# code, adapting to new API signatures.
- What C# testing frameworks does Atlas support for validation?
- Atlas supports `xUnit via dotnet test` for validating C# code after dependency upgrades, running tests through its `bash` tool to ensure no regressions.
- How does Atlas ensure C# code formatting is consistent?
- Atlas can apply `dotnet format` using its `bash` tool to ensure all modified C# files adhere to the project's specified formatting standards.
- How does Atlas provide safety and review for C# code changes?
- Atlas offers permission-gated tool calls, drafts plans in a read-only agent, and presents unified diffs for every C# file edit, requiring developer approval before writing.
- Does Atlas integrate with git for C# projects?
- Yes, Atlas reads `git` branches, status, and diffs, and can stage and create commits on your behalf, providing a complete `git` workflow for C# developers.
- How does Atlas get release notes for C# libraries?
- Atlas uses its `webfetch` tool to retrieve the library's release notes or changelog, providing crucial context for understanding breaking changes in C# dependency upgrades.
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