Comet Phase 2: Design

On first entering a phase, handing off to a new Agent, or restoring context, read and follow Task Context and Artifact Language. Prefer the current continuation or claimed Action's contextRequest; do not retrieve repeatedly during uninterrupted work in the same phase.

After the entry returns layout, use comet-classic/reference/classic-layout.md to resolve each logical root. Reuse this protocol if it is already in context. Route all OpenSpec CLI calls through the adapter and use the bound <classic-*> roots for file paths; do not run an extra root show first.

SDK Run path

On first entering the current SDK phase, handing off to a new Agent, or restoring context, read phase entry and recovery and the current phase's section in that reference. Reuse them when already available and still valid in this session. Continue with the phase below; recovery routes based on nextAction.kind apply only to older responses without a continuation mode.

Reuse the latest valid response for the same change, workspace, and Run: agent.continuation, data.nextAction, phase, revision, and path summaries. Run comet state next <change-name> --json only for cold recovery, workspace or external state changes, a stale response version, or missing information needed for the current step; loading the next Skill is not a reason to query again. Runtime still validates current versions and evidence on writes; cached context cannot bypass checks or approval. For data.runtimeFormat: sdk, use this section for state changes; use the Design section of SDK execution methods for exploration, questions, and formal document requirements. data.phase must be design. If Build has begun, return to its entry. For nextAction.kind: reconcile, run comet state check <change-name> design --recover --json and establish the claimed Action's original outcome before proposing or redispatching.

1. At full.design.handoff, reuse layout and references from the current response; run comet state check <change-name> design --json only when they are missing. Read the current OpenSpec proposal, tasks, delta specs, and relevant existing design.md. Develop candidate solutions under the Design section of SDK execution methods and keep brainstorm-summary.md current, marking unapproved content as a candidate. There is no SDK handoff packet yet; do not call legacy comet handoff ... --write or substitute a handwritten summary.
2. For a needed Spec Patch, explain it and obtain explicit agreement under the Design confirmation rules in SDK execution methods before editing the delta spec. Reclarify material scope changes. When sources are stable, run comet state propose-design <change-name> --proposal "<candidate-summary>"; the summary must cover the proposed design, tradeoffs, risks, and Spec Patch. Save data.wait.proposalHash as <proposalHash>. This creates the traceable handoff. Use data.configuration.handoffContext from the proposal response, querying comet state next <change-name> --json only if it is missing, and verify the Markdown packet matches the candidate and source files. Reuse an existing pending Wait on recovery.
3. Present the design under the Design confirmation rules in SDK execution methods and ask the user to approve, request changes, or defer. Submit comet state decide-design <change-name> --proposal-hash <proposalHash> --choice <approved|rejected> only for an explicit approval or rejection. Rework and propose again after rejection; leave the Wait untouched when deferred. If source or handoff drift invalidates approval, investigate rather than applying an old decision.
4. After approval, write the single Design Doc with required frontmatter. If recovery already points to full.design.document, continue here. Run directly comet state complete-design <change-name> --design-doc <design-doc-ref> --approval-hash <proposalHash>. On failure preserve the Run and address the specific cause. Runtime synchronizes the actual state file; the Agent does not manually advance its phase. Route to the Build Action and continuation from the same successful response; run comet state next <change-name> --json only if continuation information is missing.

Compat path

The remaining original Runtime steps apply only to runtimeFormat: compat. Read Compat operations and continue its current phase. SDK does not load that reference.