api-sync

name	api-sync
description	Check upstream Basecamp API changes and sync the Smithy spec. Compares bc3 API docs and app code against the tracked bc3 revision in spec/api-provenance.json, identifies what changed, and optionally updates the Smithy spec and regenerates SDKs.
disable-model-invocation	true
argument-hint	[check|sync|update-rev]

API Sync Skill

You are synchronizing the Basecamp SDK's Smithy spec against upstream API changes.

Inputs

• mode: {{ arguments.mode | default: "check" }}

Upstream repo

• bc3 (canonical source): basecamp/bc3
  • API reference docs: watch doc/api/
  • Rails app/API implementation: watch app/controllers/

The public basecamp/bc3-api repo is a mirror for documentation consumption, not a provenance input.

Phase 1: Load State

1. Read spec/api-provenance.json to get the last-synced revision for bc3.

Phase 2: Check Upstream

List files changed in the watched paths since the last sync.

For bc3 API docs (doc/api/):

gh api repos/basecamp/bc3/compare/<bc3.revision>...HEAD \
  --jq '[.files[] | select(.filename | startswith("doc/api/"))] |
    if length == 0 then "  (no changes in doc/api/)"
    else .[] | .status[:1] + " " + .filename
    end'

For bc3 API implementation (app/controllers/):

gh api repos/basecamp/bc3/compare/<bc3.revision>...HEAD \
  --jq '[.files[] | select(.filename | startswith("app/controllers/"))] |
    if length == 0 then "  (no changes in app/controllers/)"
    else .[] | .status[:1] + " " + .filename
    end'

Summarize the changed files by API domain (todos, messages, people, etc.). If there are no changes in either watched path, report "up to date" and stop.

If mode is check, stop here after reporting what changed.

Phase 3: Sync Spec (mode=sync only)

For each changed doc file in bc3:

1. Fetch the upstream doc from basecamp/bc3:

   gh api repos/basecamp/bc3/contents/doc/api/<path> --jq '.content' | base64 -d
   

2. Read the corresponding Smithy operations in spec/basecamp.smithy and spec/overlays/
3. Identify gaps: missing operations, changed fields, new parameters
4. Propose specific Smithy changes and apply after confirmation

For controller changes in bc3, cross-reference them with doc/api/ to identify behavioral changes that affect the spec.

Phase 4: Regenerate (mode=sync only)

After spec changes are applied:

make smithy-build
make -C go generate
make url-routes
make ts-generate && make ts-generate-services
make rb-generate && make rb-generate-services
make provenance-sync
make check

Fix any issues that arise during generation or checks.

Phase 5: Update Revision (mode=sync or update-rev)

Get the current bc3 HEAD:

gh api repos/basecamp/bc3/commits/HEAD --jq '.sha'

Write the new revision and today's date to spec/api-provenance.json:

{
  "bc3": {
    "revision": "<new-sha>",
    "date": "<today>"
  }
}

Then run make provenance-sync to update the Go embedded copy.

Output

Report a summary of:

• What changed upstream (by domain)
• What spec changes were made (if sync mode)
• New revision SHA stamped
• Any warnings or issues encountered