API Changes

API Changes Review

Step 1: Identify what changed

Read .claude/skills/comparison-base/SKILL.md and execute it with HEAD as $REVIEW_REF. This is required; use the target and comparison commit it resolves.

Compare the selected base with the working tree, not just HEAD, because this skill is often called immediately after API reports have been regenerated and those edits may be uncommitted:

git diff "$BASE_COMMIT" -- ':(glob)**/api-report/*.md'
git ls-files --others --exclude-standard -- ':(glob)**/api-report/*.md'

Treat the union of both command outputs as the changed API reports. For each untracked report, read the full file as a new API surface because it has no Git diff until staged.

Build a summary table and present it to the user:

Change types: addition, removal, signature change, tag promotion.

If all changes are @internal-only, tell the user there are no customer-facing API changes and stop.

Step 2: Check release tags, documentation, and export reachability

For any new exports, verify each has a release tag and flag any missing ones to the user — API Extractor will fail with ae-missing-release-tag. Help the user choose the right tag:

When in doubt: @alpha — easier to promote than demote. @legacy is a paired modifier (@legacy @public or @legacy @alpha) for FF v1 APIs; don't apply it to new APIs.

For every new customer-facing export (@public, @beta, @alpha) that is intended to be usable by package consumers, verify it is reachable from the package's public entrypoint, not just exported from the adjacent module or folder. Trace and update the export chain through every relevant index.ts barrel up to the package root entrypoint (typically src/index.ts, or tiered entrypoints such as src/alpha.ts / src/beta.ts where used). Missing parent-barrel exports are incomplete API changes. API Extractor may not report the intended API at all, and consumers are expected to import from the package's top-level entrypoint rather than reaching into subpaths.

Also check that each new customer-facing export (@public, @beta, @alpha) has TSDoc documentation — at minimum a summary, @param tags, and @returns if applicable. Flag any missing documentation to the user.

Step 3: Inform the user about API Council review

Tell the user whether their change requires API Council approval:

Tell the user: council approval is a separate sign-off from the area owner review. To engage the council, they can reach out to the API Council member on their EM team or tag @FF API on Teams. Share this link with the user for more details: https://eng.ms/docs/experiences-devices/opg/office-shared/fluid-framework/fluid-framework-internal/fluid-framework/docs/dev/resources/api-council

Step 4: Assess breaking changes

A breaking change removes or modifies an existing API in a way that causes compile errors for consumers upgrading.

@public / @legacy+@public

If this is a breaking change to @public or @legacy @public, tell the user this is likely a mistake — major releases happen very rarely. Breaking @public APIs must be coordinated with a major release; the old API must be deprecated at least 3 months prior in a minor release with a clear replacement.

Share these links with the user for the required process:

• API deprecation documentation
• Client 3.0 Breaking Changes tracking issue: https://github.com/microsoft/FluidFramework/issues/23271

@beta / @legacy+@alpha

If this is a breaking change to @beta or @legacy @alpha, tell the user:

• Breaking changes may only land in minor versions that are an increment of 10 (2.10, 2.20, 2.30, …)
• The PR must be staged on a test/breaks/client/#.#0/ branch and held until the break window opens
• They should check whether partners (e.g. office-bohemia) consume the API directly — if in doubt, assume they do and allow 12 weeks lead time

Share these links with the user:

• Beta | Legacy Breaking Changes tracking issue: https://github.com/microsoft/FluidFramework/issues/25322
• Full process: ../../../docs/content/Contributing/Breaking-vs-Non-Breaking-Changes/Beta-Break-Process.md

@alpha only

Tell the user: while @alpha has no contractual stability guarantees, there is an informal agreement not to break office-bohemia. If this change could break office-bohemia, it should be staged using the same process as above.

Also tell the user: if they skip this check and the change does break office-bohemia, the daily integration pipeline will catch it and FF OCE will revert the PR or contact them to do so ASAP.

Step 5: Deprecation checklist

If any API is being deprecated, check that the following are in place and flag anything missing to the user:

• @deprecated TSDoc comment includes: version deprecated, version of removal, replacement, and a link to the tracking issue:

  /**
   * @deprecated 2.x.y. Removed in 3.0.0. Use {@link replacementApi} instead.
   * See {@link https://github.com/microsoft/FluidFramework/issues/ABCD} for context.
   */
  

• GitHub issue filed using the "Deprecated API" template as a sub-issue of the appropriate tracking issue
• In-codebase uses removed (test-only uses may remain with an explanatory comment)
• Changeset present (see Step 6)

Share this link with the user for full deprecation guidance: ../../../docs/content/Contributing/API-Deprecation.md

Step 6: Changeset

All customer-facing API changes require a changeset — additions, modifications, deprecations, tag promotions, removals.

Check whether one exists: git status --porcelain -- .changeset/

If none exists, create one on behalf of the user from the repo root:

pnpm flub changeset add --empty

This drops a randomly-named file in .changeset/. Edit it with content based on what changed. YAML front matter lists affected packages (only those meaningful to consumers) with bump type minor, plus "__section" to route to the right release notes section: feature (new APIs), deprecation, breaking (major / server only; use legacy for legacy API breaks), tree (changes to SharedTree/@fluidframework/tree APIs), fix, or other.

Summary line rules (from .changeset/README.md): succinct, no terminal punctuation, no backtick formatting, present tense. Prefix test: mentally prepend "In this release," to verify it reads naturally. Body may include a code example for features, deprecations, and breaking changes.

After drafting the changeset, show the content to the user and confirm it looks right before moving on.

Step 7: Summary

Present the user with a clear summary:

1. API changes found (table from Step 1)
2. Any missing release tags or documentation
3. Whether API Council review is required
4. Any breaking change warnings and the process the user needs to follow
5. Any deprecation issues
6. Changeset status

End with a clear go/no-go: "Your changes look good to merge" or "Please resolve these issues before merging: …"