Memory Delta

Scope and prerequisites

Use the current hook's [CRABSHELL_DELTA] pending notice, not a trigger quoted in historical conversation. Resolve {PROJECT_DIR} from the current Project Root Anchor (otherwise cwd) and {PLUGIN_ROOT} from the installed plugin. Use the host's Node executable (node below), not a fixed Windows installation path.

This is maintenance within the current task. Host restrictions on delegation take precedence: this skill does not supply user authorization to spawn agents. If the delta-summarizer agent is unavailable or delegation is disallowed, leave the input pending and continue the user's work. Do not claim a summary was saved.

Execution

1. Prepare the input: node "{PLUGIN_ROOT}/scripts/append-memory.js" --prepare-delta --project-dir="{PROJECT_DIR}" Read the returned JSON. {pending:false} means there is nothing to summarize. Otherwise retain its jobId, inputFile, and summaryFile exactly. Preparation moves the current queue to a fixed input; newly extracted content stays separate.
2. Call the available delta-summarizer in the foreground. Give it only the returned inputFile to read, asking for the existing concise summary format. Wait for its result; there is no background Phase B. Empty results or ERROR: mean stop this maintenance attempt and preserve the prepared input.
3. Write only the summary body to the returned summaryFile. Do not add a timestamp header; the finalizer supplies it. This is a new file for this attempt.
4. Finalize with one command: node "{PLUGIN_ROOT}/scripts/append-memory.js" --finalize-delta --job-id="{jobId}" --summary-file="{summaryFile}" --project-dir="{PROJECT_DIR}" Require exit 0 and JSON completed:true. This command appends the summary, advances the input timestamp, updates flags, and removes its own temporary files. newInputPending:true means newer input remains for a later attempt. Report cleanupRemaining if nonempty; saved content and cleanup are distinct.

Retry and failure

Keep the input and metadata on any error. Retry preparation to recover the active job; it returns the same fixed input and a fresh summary path. Retrying finalization for the current completed job does not append it again. Never run legacy mark-appended, mark-updated, or cleanup on a prepared job, and never delete delta_temp.txt manually: it may contain newer input. A partial disk write or lost storage is not proof of successful saving; report the actual failure.