Planner Pattern — Problem

Pattern: Planner
Component: problem.md
Version: 1.2 | Updated: 2026-07-29

Statement

Multi-file or cross-boundary work handed straight to a coder agent yields token-local correctness and system-level failure: missed dependencies, invented contracts, and 2–3× rework.

Measurable symptoms

Symptom	How you detect it
Second architectural pass	More than ~30% of AI multi-file PRs need a redesign mid-flight
Surprise paths	PR touches files never listed in an approved plan
Interface invention	New API shapes or schema columns appear without human review
No revert story	Deployable change ships without a named rollback

Root cause

Next-token models optimize local coherence inside a context window. Ordering, blast radius, and contract stability are not enforced unless externalized as a reviewed plan.

What breaks when this pattern is skipped

Coder asks architectural questions mid-implementation
Reviewer finds AuthZ or schema changes that were never planned
Hotfix expands because the original change had no return path

Non-goals of this pattern

Not a product requirements substitute
Not a dumping ground for implementation code
Not required for single-file typos, pure config toggles, or docs-only edits

Failures — recovery table
Workflow — ordered steps
Checklist — exit criteria

Changelog

1.2 (2026-07-29): Planner problem page expanded with skip-impact and operator symptoms.