Consolidate progressive-context guidance without weakening workflow contracts

[ladislas]

Summary

Consolidate progressive-context guidance without weakening workflow contracts. Priority: P3.

Motivation

Shared, implementation, commit, TDD, and extension instructions repeatedly restate progressive-reading and reread guidance. Consolidation could reduce instruction cost, but historical corrections mean text deletion alone is not evidence of improvement.

Reviewed source: shared/SHARED_APPEND_SYSTEM.md. Revalidate against current main before implementation.

Acceptance Criteria

• Inventory duplicated rules and identify the canonical owner and workflow-specific exceptions.
• Review relevant history, including Make /pac-llat redundant GitHub read prevention reliable #397, Avoid redundant GitHub issue re-fetches in /pac-lwot #405, Prevent /pac-lwot scope drift after resumed execution #438, and Audit behavior ownership and universal defaults across mypac #411, before removing safeguards.
• Preserve no-op/resume/closure behavior and the existing permission/ownership contracts in representative behavioral scenarios.
• Measure instruction-size changes and compare relevant workflow outcomes; record the result and any retained duplication with its reason.
• Implement only consolidation supported by the review; a documented no-change disposition is acceptable if benefits do not justify behavioral risk.

Scope and verification

Assess shared guidance plus pac-lwot, pac-commit, pac-tdd, and extension-development instructions. Prefer doing the Copilot, AFK, and PRD corrections first to reduce editorial churn. Live model evaluations require explicit session authorization.

Run affected regression coverage and required repository checks for any implementation; update relevant documentation/changelog under repository conventions. Record measurements and decisions durably in this issue or its linked PR.

Type

HITL — requires a policy or design review informed by the investigation before committing to the implementation approach. Investigation can proceed autonomously; publication follows existing authorization rules.

Parent

#466

Blocked by

• Retain committed implementation evidence in Pi evaluations #467 — retain evaluation evidence before relying on evaluation outcomes.
• Terminate evaluation process trees on timeout #468 — ensure evaluation timeouts clean up reliably.

Static inventory can begin now; behavioral evaluation using the harness follows these fixes.