Plan backlog items into agent tasks

Load the ado-backlog skill first: it has the project settings, tools, fields, tags and WIQL. This skill runs in the main session (it talks to Azure DevOps); the planning itself is done by the qugents:planner agent.

Input: a PBI id (/qugents:ado-plan 123) or nothing, which means every PBI tagged agent-plan.

Steps per PBI

1. Read. wit_work_item get with relations: title, description, acceptance criteria, tags, parent Feature/Epic (read its title/description for context), existing child Tasks, and list_comments (the PO may have answered earlier questions there).
2. Check readiness. If acceptance criteria are missing or the item is too vague to plan, do not invent them: add a comment with 1–5 concrete questions, add tag needs-human, and move to the next PBI.
3. Plan. Spawn qugents:planner with: the PBI title, description and acceptance criteria verbatim; the parent's goal; the PO's comments; the existing child tasks (plan only the gap); and the instruction "Output tasks in your standard format. Each task must be one pull request."
4. Create tasks. One wit_work_item_write add_child call under the PBI with all tasks in order (workItemType: "Task", format: "Markdown"):
   • Title: T<n> — <imperative title>
   • Description (Markdown): Why, Acceptance criteria (Given/When/Then list), Backend, API contract, Frontend, Test cases, Depends on. Keep the planner's content as it is.
     Then one update_batch on the new ids: /fields/System.Tags = agent-proposed and /fields/Microsoft.VSTS.Scheduling.RemainingWork = 2 (S), 4 (M) or 8 (L). add_child cannot set these itself.
5. Link dependencies. For "Depends on: T", link the new task to T as successor/predecessor.
6. Update the PBI. Tags: remove agent-plan, add agent-planned. Comment:

Agent plan: <n> tasks created (T1–T<n>), tagged agent-proposed.
Next step (PO): review/edit the tasks and change agent-proposed → agent-ready on the ones to build.
Open questions: <planner's open questions, or "none">
Risks: <planner's risks, or "none">

If the planner has open questions that block a task, still create the other tasks, and tag the PBI needs-human as well.

Rules

• Never tag anything agent-ready. That is the PO's approval.
• Never edit the PBI's description, acceptance criteria or state.
• Re-running on a PBI that already has agent-planned only adds tasks for new scope the PO asked for in a comment; it never duplicates existing tasks.
• Finish with a short summary to the user: PBIs planned, tasks created (ids + titles), questions raised.