Grace Plan

<skill>
<purpose>Convert one approved active `GraceChangeSpec` into the executable `GraceChangePlan`; do not implement source code.</purpose>

<inputs>
- Required: `.grace/changes/active/C-CHANGE-ID/spec.xml`
- Optional: sibling `design-context.xml`
- Current state: `.grace/context`, graph and verification indexes, and their routed documents
</inputs>

<preflight>

• Require .grace/changes/active/C-CHANGE-ID/spec.xml with GraceChangeSpec, status approved, and exactly one matching direct C-* wrapper.
• Refuse draft, rejected, cancelled, applied, or superseded specs.
• Treat optional design-context.xml as explanatory; spec.xml wins on conflict.
• Run grace lint --path PROJECT --assertions current before planning and surface stale or invalid active baselines. </preflight>

<approved_plan_immutability>

• If plan.xml already exists with status approved, stop before writing.
• Do not refresh BaselineAssertions, TargetAssertions, DurableScope, ObservedWriteScope, or tasks in place.
• Create a new C-* bundle and mark the old bundle superseded with an explicit replacement reference. </approved_plan_immutability>

<must_do> Produce plan.xml from references/change-plan-template.xml as draft unless the user explicitly approves the completed plan. Require a matching C-* wrapper, meaningful intent, non-empty machine-checkable baseline and target assertions, explicit durable and observed scopes, and unique acyclic T-NNN tasks. A scope with no writes must use an explicit <None /> marker; prose such as "none" is invalid. Every task has one Title, one DependsOn element listing zero or more predecessors as canonical comma-separated T-NNN values (for example <DependsOn>T-001, T-002</DependsOn>), non-empty acceptance criteria, and non-empty verification commands. Dependencies form a directed acyclic graph: list only true predecessors and never linearize independent tasks into a chain to express ordering. Surface stale-state and coexistence warnings, and reject unsupported scope glob syntax instead of guessing. </must_do>

<command_phase_rules>

• current is an active-baseline preflight and is valid only before observed writes begin.
• baseline is the selected pre-edit gate, target is selected post-edit evidence, and final is the outer apply/archive gate owned by grace-execute.
• MustPassCommand contains leaf project evidence such as tests, typecheck, build, format, or package checks. Never place grace lint, grace status, or another GRACE lifecycle command inside it.
• Never put --assertions current in TargetAssertions or in task verification that runs after writes. Use selected target/final lint externally instead.
• A MustPassCommand must complete within its declared budgetSeconds (absent, the global --command-timeout applies) on the reference host; declare the budget you have measured rather than inheriting a default that will kill the command mid-gate.
• A whole-suite command whose runtime is dominated by substrate startup — containers, databases, browsers, emulators — belongs in an acceptance tier, not in the gate; never declare both a whole-suite command and the file-level commands it already re-runs. </command_phase_rules>