archival-integrity

## Context Use this skill for decision archival, history summarization, or any operation that moves entries between repository state files. A move has two halves: append to the destination, then trim the source. Treat it as data loss prevention, not text cleanup. ## Scope - Activate when moving entries between tracked Squad state files such as decision logs, histories, or inbox merges. - Allowed targets: tracked repository state files and their designated tracked archives. - Exclusions: untracked destinations, byte-delta-only validation, and trimming source content before the destination is verified. - This procedure is scoped to the local state backend unless the active backend exposes governed append, read-back, and trim operations. Runtime-owned orphan or two-layer state is not a valid archival destination; use the backend's state operation instead of editing a checkout copy. ## Patterns 1. Resolve a destination that is already tracked before writing. If the requested destination is untracked, redirect to a tracked archive or stop. 2. Append first, re-read the destination, and prove every moved heading is present. 3. Compare entry counts before and after the append. Trim only when the count increased by exactly the selected number of entries. 4. Report measured `removed from source / added to destination` counts. Do not use byte deltas as an integrity signal. 5. When inserting an inbox body beneath a `###` entry, demote its shallowest heading to `####` while preserving relative levels and fenced-code content. 6. Prefer `archiveEntries()`, `prepareInboxBodyForMerge()`, and `formatArchivalReport()` from `packages/squad-sdk/src/state/io/archival.ts` over hand-rolled archival logic. ## Stop conditions - Stop if the destination is not already tracked. - Stop if the appended headings cannot be re-read from the destination. - Stop if the entry-count increase does not exactly match the selected move set. - Stop if the active backend is non-local and does not provide governed archival operations. - Stop if state appears orphaned, split across runtime and checkout layers, or owned by another process without an explicit handoff. ## Examples The archival tests in `test/state/archival.test.ts` cover append failures, swallowed writes, untracked destinations, CRLF inputs, count verification, and fence-aware heading demotion. ## Anti-Patterns - Creating a timestamped archive under a git-excluded directory and assuming it will persist - Deleting source content before the destination has been verified - Reporting “no archival required” without measuring eligible entries - Treating a matching file-size delta as proof that the content survived