Everything under /api/v1/ is the stable namespace. Build against it and it keeps working: fields may be added, but existing fields, paths, and semantics do not change out from under you.
When something has to break
A breaking change ships as a new version, not an edit to /api/v1/. The old behavior then enters a deprecation window of 90 days before it is removed, so an integration you are not actively maintaining still has a quarter to catch up.
Deprecations and API changes are announced in the changelog. That is the one place to watch.
Rate limits
Limits are per user, per minute. The ones that matter when you integrate:
| Surface | Limit |
|---|---|
| API requests (PAT or JWT) | 200/minute |
| Inbound MCP tool calls | 60/minute |
| Sending a brief to a connected tool | 30/minute |
| Emailing a brief to yourself | 12/minute |
| Emailing a brief to named recipients | 10/minute |
Going over returns 429 Too Many Requests with a Retry-After header holding the seconds to wait. Honor it and back off; hammering a 429 only resets your window.