Sb Drive

Drive the active milestone to its next real boundary

Apply project language style

Before authoring any artifact or user-facing prose, read:

specbind rule read language-style --for consume

Apply returned policy only to natural-language prose. NO_CHANGE RULE_ABSENT means no additional project preference; any ERROR line stops the workflow.

Use this Skill when the user asks to drive, continue, or advance the active milestone as far as possible. A request for one Roadmap item's implementation still belongs to sb-implement.

You are a thin controller. Existing Skills own all artifacts, judgments, progress, and checkpoints. The CLI owns lifecycle state. Never author their work or retain a competing schedule.

Optional replan authority

When --replan is present, or the maintainer explicitly requests delegated replanning, read Authorized replan routing completely before scheduling work. The option or explicit request is itself the authority; do not ask for it again. Without that authority, do not load the procedure and retain the ordinary approval and rewind confirmations below.

1. Read the only scheduler

specbind milestone status --json

If there is no active milestone, route to sb-discovery and stop. If state health is inconsistent, report its diagnostics. Do not guess a repair.

Use only the returned ordered actionable entries, their typed handler, action, and exact commandOperand, plus waitingFor, current blockers, and release blockers. Never parse the Roadmap to compute waves. Keep a run-local set of action keys already attempted at unchanged state: <action>:<commandOperand-or-milestone>.

A pending Direct item is mechanically actionable once any required shared Contract Review is fresh, even when its summary later proves it was classified too narrowly. Dispatch its exact item and summary to sb-implement; do not pre-classify Roadmap prose in Drive or treat a clean status as semantic approval of the Direct kind.

2. Dispatch one owning workflow at a time

Choose the first safe actionable entry not parked at the current state. Never reconstruct an owner from action or maintain a local action-to-Skill table.

• handler.kind=skill names the installed owning Skill in handler.target. Dispatch a fresh subagent with the exact item, action, handler mode, commandOperand, applicable authority, project working directory, project-local executable and PATH facts, and exact applicable project instruction paths. Require that owner to read those instructions and load the exact handler.target Skill before it delegates any internal role. The dispatched workflow then reads its own domain inputs.
• A Skill target is the complete owning workflow package, not a similarly named registered internal agent role. Tell the fresh subagent to execute the exact handler.target Skill through its terminal handoff. For handler.target=sb-implement, never dispatch specbind-implementer or specbind-reviewer directly: those roles are internal to sb-implement, which owns review, Task progress, and the checkpoint. An internal READY_FOR_REVIEW result is not an owning-workflow result and must not return control to Drive.
• handler.kind=guarded_cli names the accepted guarded command. Run it only when this Skill's existing authority boundary permits that exact action.
• handler.kind=boundary names the next explicit workflow. Report it and stop; never invoke that workflow from Drive.
• An unknown kind, target, or mode is an incompatible product surface. Stop rather than guessing a route.

handler.target=sb-adopt with handler.mode=reverse_resume does not turn a generic Drive request into reverse Gate authority. Unless the maintainer explicitly authorized reverse continuation, park it as HUMAN_DECISION and name sb-adopt as the continuation owner.

Use one mutating dispatch at a time. Do not launch dependency-wave items in parallel and do not predict path conflicts.

Planning still owns its delegation confirmation. Invoking Drive without --replan does not grant gate approvals. Pass through only authority the user explicitly supplied. A missing confirmation is attention, not permission to approve or a reason to interrupt while unrelated implementation remains reachable.

If sb-implement reports that a Direct summary requires canonical artifacts or an unsettled product or architecture decision, normalize the handoff as REROUTABLE plus HUMAN_DECISION. Park it for Discovery and continue every independent safe action; do not expect milestone status to infer that semantic classification from the summary.

3. Re-read after every handoff

After every dispatch, run:

git status --short
specbind milestone status --json

The fresh status decides what happened. Do not accept the subagent's narrative as lifecycle evidence.

• If authoritative state advanced and the handoff is safe, clear obsolete waits and select again.
• If the attempted action remains unchanged, add it to attention. Do not re-dispatch it in this run unless the owning workflow explicitly returned RETRYABLE within an unspent retry bound.
• Preserve every owning workflow's retry and remediation limit. Drive never resets one.
• Except for the attributable same-recovery handoff defined by Authorized replan routing, if the worktree contains partial, rejected, unrelated, or unattributed work, stop the run. Never reset, stash, revert, clean, or manufacture a WIP commit to switch items.

4. Separate the cause from stopping the run

Normalize a returned or re-read condition to one cause:

• RETRYABLE — the same owner may repeat within its existing bound
• REPAIRABLE — the owner may apply concrete review findings within its bound
• REROUTABLE — an earlier owning phase is required
• WAITING — a dependency or global barrier is not satisfied
• BLOCKED — the owning surface established that the item cannot progress
• HUMAN_DECISION — meaning, scope, authority, or irreversible consequence needs the maintainer
• EXTERNAL_BLOCK — the environment cannot satisfy a prerequisite
• COMPLETE — the delegated boundary is complete

Then make a separate scheduler decision:

• CONTINUE_ELSEWHERE when status exposes another independent safe action;
• STOP_RUN when no safe reachable action remains or the shared worktree makes switching unsafe; or
• COMPLETE when status reaches release_ready.

BLOCKED and HUMAN_DECISION do not mean immediate interruption. Park the affected item, let its descendants wait, and continue another branch. An unfinished Design prevents Contract Review but not other reachable Design. An unfinished implementation prevents its descendants and milestone validation but not independent implementation.

5. Keep attention run-local

For every parked condition retain only this run's report data:

• owner and affected item or milestone barrier;
• cause and concise evidence;
• action or decision needed to resume;
• descendants or global barriers it prevents; and
• whether work continued elsewhere.

Create no queue, checkpoint, batch status, or authority artifact. Durable Task blocks and lifecycle progress remain in their existing owning surfaces. A later Drive invocation reconstructs everything from fresh status.

Never silently invalidate an approved gate, change Roadmap scope, choose a release version, reclassify Direct work, accept breaking Contract consequences, use credentials, perform destructive recovery, or take external action. Those become HUMAN_DECISION attention unless the Design/Contract/Tasks consequence is already covered by Authorized replan routing. Requirements rewinds always retain explicit confirmation; Design and Tasks do so without replan authority. A Direct item that needs canonical artifacts returns to Discovery.

6. Stop before Release

The successful delivery boundary is release_ready. Never dispatch sb-release, execute adapter Prepare/Publish/Verify instructions, or call release finalization. If the target release is unbound and none was explicitly supplied, park bind_release as a human decision and finish other reachable work first.

7. Report one accumulated handoff

Report in the project's language:

• the milestone and boundary reached;
• owning workflows completed and authoritative state gained;
• every attention item, its cause, and affected descendants or barrier;
• decisions now required, grouped after reachable work is exhausted;
• external blocks and unsafe-worktree details;
• the next safe action, if one exists; and
• that Release execution did not run.

Boundaries

• Orchestrate only; author no phase or implementation content.
• One mutating owner at a time in the initial implementation.
• Status is the schedule; retained context is not.
• Do not turn Drive into release authority or a persistent workflow engine.