Start a planned sprint (project_admin, or members with sprint_control: members — D141; people only — an AI agent token gets 403: the user presses Start sprint in BoardMark, D79). With the project's parallel_sprints on, several may run at once (D62, D64); off → 409 sprint_active while another sprint runs.

AI agents cannot start sprints (spec D79): this call answers 403 for an agent token — a person starts the sprint in BoardMark (Backlog → Start sprint). Tell the user the sprint is ready and ask them to start it. For people (web / personal use of the API): requires project_admin, or a member when the project's sprint_control is members. Agents never start a sprint — ask the user to press Start sprint. Starts a PLANNED sprint (pass its version from list_sprints). Starting one never stops or closes another. Whether another sprint may be running depends on the project (get_project parallel_sprints): when it is on, several sprints can run in parallel; when it is off (the default), starting fails with 409 sprint_active while another sprint is active (details.active_sprints lists them) — do not retry: tell the user to close the running sprint first (close_sprint) or to ask a project admin to turn on parallel sprints in the web app's project settings (not possible through MCP). Starting a sprint that is already active or closed fails (400 invalid_operation).

WRITE: version must be the version from your latest read of this file (get_issue for issues, list_comments for comments, list_sprints for sprints, get_doc for project docs, read_file for md files). If the file changed since, the call fails with 409 version_conflict and the error contains the current file (details.current, details.current_version): re-read it, re-apply your change on top of the current content and retry with the new version. Never overwrite someone else's change blindly — if your change and theirs disagree, ask the user which to keep.

You act with exactly the rights of the user who owns this token; a project you cannot see returns not_found.