Prepare Release

Prepare a new release for the modelcontextprotocol/csharp-sdk repository. This skill assesses the appropriate Semantic Versioning 2.0.0 level based on queued changes, bumps the version, runs API compatibility and diff tools, reviews documentation, drafts release notes, and creates a pull request containing all release artifacts.

Safety: This skill creates a local branch and PR. It must never create a GitHub release. Release creation is handled by the publish-release skill after this PR is merged.

User confirmation required: This skill NEVER pushes a branch or creates a pull request without explicit user confirmation. The user must review and approve all details before any remote operations occur.

Process

Work through each step sequentially. Present findings at each step and get user confirmation before proceeding. Skip any step that has no applicable items.

Step 1: Determine Target and Gather PRs

The user may provide:

• A git ref (commit SHA, branch, or tag) — use as the target commit
• No context — show the last 5 commits on main (noting HEAD) and offer the option to enter a branch or tag name instead

Once the target is established:

1. Determine the previous release tag from gh release list (most recent published release — exclude drafts with --exclude-drafts).
2. Get the full list of PRs merged between the previous release tag and the target commit.
3. Read src/Directory.Build.props at the target commit. Extract <VersionPrefix> as the candidate version.

Step 2: Categorize and Attribute

Sort every PR into one of four categories. See references/categorization.md for detailed guidance.

Entry format — * Description #PR by @author with co-authors when present:

* Description #PR by @author
* Description #PR by @author (co-authored by @user1 @Copilot)

Attribution rules:

• Harvest Co-authored-by trailers from all commits in each PR (not just the merge commit) to identify co-authors. Do this for every PR regardless of primary author.
• For Copilot-authored PRs, additionally check the copilot_work_started timeline event to identify the triggering user. That person becomes the primary author; @Copilot becomes a co-author.
• Omit the co-author parenthetical when there are none
• Sort entries within each section by merge date (chronological)

Step 3: Breaking Change Audit

Invoke the breaking-changes skill with the commit range from the previous release tag to the target commit. Examine every PR, assess impact, reconcile labels (offering to add/remove labels and comment on PRs), and get user confirmation.

Use the results (confirmed breaking changes with impact ordering and detail bullets) in the remaining steps.

Step 4: Assess Release Version

Using the categorized PRs from Step 2 and confirmed breaking changes from Step 3, assess the appropriate Semantic Versioning 2.0.0 release level. Follow the SemVer assessment guide (owned by the bump-version skill) for the full assessment criteria.

1. Classify the release level:
   • MAJOR — if any confirmed breaking changes are present (API or behavioral), excluding changes to [Experimental] APIs
   • MINOR — if no breaking changes but new public APIs, features, or obsoletion warnings are introduced
   • PATCH — otherwise
2. Compute the recommended version from the previous release tag:
   • Increment the appropriate component (MAJOR resets MINOR.PATCH to 0; MINOR resets PATCH to 0)
3. Compare against the candidate version from src/Directory.Build.props. Flag any discrepancy:
   • Under-versioned: The candidate is lower than the recommended level. This is a concern that should be resolved.
   • Over-versioned: The candidate is higher than strictly required. This is acceptable under SemVer but worth noting.
4. Present the assessment with a summary table showing the previous release, change classification, recommended level, recommended version, and any discrepancy with the candidate. Include a brief rationale citing the most significant PRs.
5. Get user confirmation of the release version before proceeding.

Step 5: Create Release Branch and Bump Version

After the version is confirmed:

1. Create a local branch named release-{version} from the target commit (e.g., release-1.1.0).
2. Update src/Directory.Build.props:
   • Set <VersionPrefix> to the confirmed version
   • Update <PackageValidationBaselineVersion> if the MAJOR version has changed (set to the previous release version)
3. Build the solution to verify the version change compiles: dotnet build

This step creates local changes only — nothing is committed or pushed yet.

Step 6: Run API Compatibility Check

Run API compatibility validation against the baseline version. Follow references/apicompat-apidiff.md for the full procedure.

1. Run dotnet pack to trigger package validation against PackageValidationBaselineVersion
2. Capture the ApiCompat output (compatibility issues, warnings, suppressions)
3. If there are unexpected compatibility breaks:
   • Cross-reference with the breaking change audit from Step 3
   • Present any unaccounted breaks to the user
   • If breaks are intentional, add appropriate entries to CompatibilitySuppressions.xml in the affected project directory
4. Record the ApiCompat results for inclusion in the PR description

Step 7: Generate API Diff Report

Generate a human-readable diff of the public API surface between the previous release and the new version. Follow references/apicompat-apidiff.md for the full procedure, including how to install the Microsoft.DotNet.ApiDiff.Tool from the .NET transport feed.

1. Install Microsoft.DotNet.ApiDiff.Tool from the transport feed if not already installed (requires --prerelease and --add-source pointing to https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet{MAJOR}-transport/nuget/v3/index.json)
2. Download the baseline packages and build the current version in Release configuration
3. Run dotnet apidiff comparing baseline vs. current assemblies for each SDK package
4. Format the diff as markdown for inclusion in the PR description

If the ApiDiff tool cannot be installed or fails to produce output, STOP and inform the user. Present the error and ask how to proceed. Do not fall back to a manual summary — the user must decide whether to troubleshoot, skip the API diff, or abort.

Step 8: Review and Update Documentation

Review repository documentation for changes needed to compensate for or adapt to this release:

1. NuGet package READMEs — Validate that code samples in README.md and src/PACKAGE.md compile against the current SDK. Follow references/readme-snippets.md for the validation procedure. Propose fixes for any API mismatches.
2. Conceptual documentation — Review docs/ for content affected by the changes in this release. Update references to changed APIs, new features, or removed functionality.
3. Versioning documentation — If the release introduces new versioning-relevant policies (new experimental APIs, obsoletion changes), verify docs/versioning.md reflects them.
4. Changelogs — If the repository contains changelog files (e.g., CHANGELOG.md), update them with the release information. If no changelogs exist, skip this sub-step and note it in the summary.

Stage all documentation changes for inclusion in the release commit.

Step 9: Draft Release Notes

Compose the release notes that will appear in the PR description and serve as the foundation for the publish-release skill. This is a draft — the final release notes will be refreshed when the GitHub release is created.

1. Preamble — Draft a short paragraph summarizing the release theme. Present it to the user for review and editing. The preamble is required.
2. Breaking Changes — sorted most → least impactful (from Step 3 results). Include the versioning docs link.
3. What's Changed — chronological; includes breaking change PRs
4. Documentation Updates — chronological
5. Test Improvements — chronological
6. Repository Infrastructure Updates — chronological
7. Acknowledgements:
   • New contributors (first contribution in this release)
   • Issue reporters (cite resolving PRs)
   • PR reviewers (single bullet, sorted by review count, no count shown)
8. Full Changelog link

Omit empty sections. Present each section for user review before proceeding.

Step 10: Commit Changes

Commit all changes to the release-{version} branch:

1. Stage all modified files (version bump, compatibility suppressions, documentation updates, changelog updates)
2. Commit with message: Prepare release v{version}
3. Do not push yet

Step 11: Present Release Summary

Present all of the following details to the user for review. The user must confirm every aspect before proceeding to Step 12.

1. Version number with brief rationale for why this SemVer level was selected
2. Branch name (e.g., release-1.1.0)
3. Remote the branch would be pushed to (show the configured remote, typically origin)
4. Files changed — list every file modified in the commit with a one-line summary of what changed in each:
   Copy

   src/Directory.Build.props — Version bumped from 1.0.0 to 1.1.0
   src/ModelContextProtocol.Core/CompatibilitySuppressions.xml — Added 2 new suppressions
   README.md — Updated code sample for new API
   docs/experimental.md — Added new experimental API reference
   

5. Draft release notes — the complete release notes from Step 9
6. API Compatibility results — the ApiCompat output from Step 6
7. API Diff report — the API diff from Step 7
8. Proposed PR title (e.g., Release v1.1.0)
9. Proposed PR description — the assembled content combining release notes, ApiCompat, and ApiDiff

After presenting all details, explicitly ask the user:

Would you like to push the branch and create the pull request?

Do not proceed without explicit "yes" confirmation.

Step 12: Push Branch and Create Pull Request

Only after explicit user confirmation in Step 11:

1. Push the release-{version} branch to the remote
2. Create a pull request:
   • Title: Release v{version}
   • Base: default branch (typically main)
   • Head: release-{version}
   • Description: The assembled PR description (see PR Description Template below)
   • Labels: Apply appropriate labels (e.g., release)
3. Present the PR URL to the user

Important: No draft GitHub release is created at this point. The publish-release skill handles release creation after this PR is merged.

Edge Cases

• PR spans categories: categorize by primary intent
• Copilot timeline missing: fall back to Co-authored-by trailers to determine whether @Copilot should be a co-author; if still unclear, use @Copilot as primary author
• No breaking changes: omit the Breaking Changes section from release notes entirely
• Single breaking change: use the same numbered format as multiple
• No user-facing changes: if all PRs are documentation, tests, or infrastructure, flag that a release may not be warranted and ask the user whether to proceed
• Version discrepancy: if the candidate version from Directory.Build.props doesn't match the SemVer assessment, present the discrepancy and let the user decide the final version
• No previous release: if this is the first release, there is no previous tag; gather all PRs merged to the target
• ApiCompat tooling unavailable: fall back to dotnet pack output; note in the PR description that full ApiCompat was run via package validation only
• API diff tool installation fails: do not fall back to a manual summary; pause and present the installation error to the user, offering options to troubleshoot, skip the API diff section, or abort the release preparation
• No changelogs in repo: skip changelog updates; note in the summary
• Branch already exists: if release-{version} already exists locally or remotely, ask the user whether to reuse it, delete and recreate, or choose a different name
• PackageValidationBaselineVersion update: when bumping MAJOR version, update the baseline to the previous release version; when bumping MINOR or PATCH, keep the existing baseline
• CompatibilitySuppressions.xml: when intentional breaks are found, add suppression entries and include the file in the commit; existing suppressions should be preserved
• User declines PR creation: if the user declines at Step 11, leave the local branch intact so they can review, modify, or push manually

PR Description Template

The PR description combines release notes, ApiCompat, and ApiDiff into a single document. Omit empty sections.

# Release v{version}

[Preamble — summarize the release theme]

## Release Notes

### Breaking Changes

Refer to the [C# SDK Versioning](https://csharp.sdk.modelcontextprotocol.io/versioning.html) documentation for details on versioning and breaking change policies.

1. **Description #PR**
   * Detail of the break
   * Migration guidance

### What's Changed

* Description #PR by @author (co-authored by @user1 @Copilot)

### Documentation Updates

* Description #PR by @author

### Test Improvements

* Description #PR by @author

### Repository Infrastructure Updates

* Description #PR by @author

### Acknowledgements

* @user made their first contribution in #PR
* @user1 @user2 @user3 reviewed pull requests

**Full Changelog**: https://github.com/modelcontextprotocol/csharp-sdk/compare/previous-tag...release-{version}

---

## API Compatibility Report

[ApiCompat output — pass/fail status per package and any issues or suppressions]

## API Diff Report

### ModelContextProtocol.Core

[API diff — additions, removals, changes]

### ModelContextProtocol

[API diff — additions, removals, changes]

### ModelContextProtocol.AspNetCore

[API diff — additions, removals, changes]

Release Notes Template

The release notes section within the PR description uses the same format as the final GitHub release notes (used by the publish-release skill). This ensures consistency between the PR and the published release.

Omit empty sections. The preamble is always required — it is not inside a section heading.

[Preamble — REQUIRED. Summarize the release theme.]

## Breaking Changes

Refer to the [C# SDK Versioning](https://csharp.sdk.modelcontextprotocol.io/versioning.html) documentation for details on versioning and breaking change policies.

1. **Description #PR**
   * Detail of the break
   * Migration guidance

## What's Changed

* Description #PR by @author (co-authored by @user1 @Copilot)

## Documentation Updates

* Description #PR by @author (co-authored by @user1 @Copilot)

## Test Improvements

* Description #PR by @author (co-authored by @user1 @Copilot)

## Repository Infrastructure Updates

* Description #PR by @author (co-authored by @user1 @Copilot)

## Acknowledgements

* @user made their first contribution in #PR
* @user submitted issue #1234 (resolved by #5678)
* @user1 @user2 @user3 reviewed pull requests

**Full Changelog**: https://github.com/modelcontextprotocol/csharp-sdk/compare/previous-tag...new-tag