One slice, not a roadmap. Shape the narrowest change that produces an observable result end to end, through every layer it touches. No phases, no layer-by-layer breakdown, no backlog: later work stays one coarse line each until new evidence makes it the next slice.
An example before any design. Write at least one Given/When/Then with an observable result. Cover the boundary where a mistake is costly to undo, such as a repeated or external side effect, lost data or widened access, not only the happy path.
Look up facts; ask only for choices. Read code, docs and the tracker instead of asking. Ask the caller at most one question, only for a choice no source can answer, with your recommendation and its tradeoff.
The repository's words. Reuse the term its code, glossary or tracker defines; never coin a parallel name.
Scope by consumer. Name the owners to edit, every live caller and test of the changed behavior, and generated companions as a class. Scope is authority, not a predicted file count.
A discriminating check: what fails today and passes after the slice.

Output

Write this block into the caller's existing intent (tracker item or conversation). It is the whole plan.

Outcome:  <who observes what, in the repository's terms>
Example:  Given <state>, when <event>, then <observable result>
Slice:    <the one end-to-end change that makes the example true>
Scope:    <owners>; consumers: <live callers and tests>; generated: <class> | none
Check:    <the test or observation that fails now and passes after the slice>
Question: <one caller choice, your recommendation, its tradeoff> | none
Later:    <deferred item and the evidence that would make it next> | none

Add an Example line only for another consequential boundary, and a non-goal only where it prevents a plausible scope mistake.

Workflow

Read the accepted intent, any existing plan or native handoff, and the relevant source owners and active constraints. Reuse the acceptance already supplied in the conversation or bead; clarify only what prevents action or judgment. To resume or replace another context, hand a slice on, plan code together with a requested retrospective, or keep an exact snapshot of conversation intent, follow resume and handoff.
Route only the uncertainty that could change the slice (table below).
Fill the block. A mechanical cross-cutting migration that cannot stay working slice by slice uses expand, migrate, contract and states where integration is required. Include recapture of affected bound evidence where necessary; in repositories with AgentOps provenance bindings, ao provenance evidence-orphans finds it. Across an epic, Navigate picks the next bead; Plan shapes that bead.
When evidence disproves an approach, keep the failed assumption, its evidence and the revised check in the existing intent. An approach change within accepted outcome and scope needs no new permission; acceptance or scope expansion needs the caller. Never relabel a failed acceptance condition as a caveat to obtain green.

Stop planning once the implementer can act and the validator can judge. More research, decomposition or review must resolve a named remaining uncertainty; reserve capacity for implementation, integration and repair.

Route uncertainty

Uncertainty	Next action
Fact a source can answer	Inspect the smallest authoritative source and cite it. Research owns deeper tracing; Domain owns disputed vocabulary. Never ask the caller to recite it.
Caller choice	Recover existing authorization first. What remains is the one question, with its concrete tradeoff; an agent cannot supply the caller's answer.
Assumption only an observation can settle	State the competing predictions and the smallest observation that separates them, using an optional probe or prototype. A persuasive design or an agent vote cannot settle unobserved behavior.
Safely deferred	Put it under Later with the event or evidence that would make it relevant. Deferral cannot hide an unanswered acceptance condition.

Resolve reversible implementation details within accepted scope. Mark inference and missing evidence; never promote either into a source fact or a settled caller choice. For consequential uncertainty that survives source checks and observation, an optional challenge returns advice or a next discriminator, never permission or acceptance. Memory recall helps only when prior evidence could change the next action.

Who decides

Use real undo cost, affected users and existing authority. A material irreversible choice outside that authority goes to the caller; prior authorization stays valid. Reviewer agreement is evidence, not permission to replace the caller's intent: explain a consequential disagreement and its support instead of silently changing acceptance. A proposed process artifact needs a concrete consumer, the decision it gates, an observed defect and a retirement condition; otherwise omit it.

Examples and naming

An example can be plain text; BDD needs no .feature file or interview. In a repository that calls queued work a Job:

Given a Job has already completed, when the worker receives it again, then its completed result is returned and its side effect is not repeated.

Write "Job", not a parallel label such as "task item". Keep the accepted example available to Implement and Validate; tests added after coding may supplement it but cannot redefine what was promised. For product planning, separate demonstrated behavior from aspiration; an ordinary feature needs no product document.

Scope

Use normalized repository-relative scope patterns. An uncovered live consumer needs a concise exact-file amendment to the caller; continue independent in-scope work meanwhile. Generated companions already in scope need no extra permission. Boundaries keep work and status in the caller's tracker and delivery under repository policy.

plan

Plan

A plan meets these rules