wiki-fold: Extractive Log Rollup

Implements a bounded subset of Mechanism 1 from [[DragonScale Memory]]: flat fold over raw wiki/log.md entries. Fold-of-folds (hierarchical level-stacking) is out of scope for this skill; see "Scope boundary" below.

A fold is additive: child log entries and their referenced pages are never modified, moved, or deleted. A fold is extractive: every outcome and theme in the output must be traceable to a specific child log entry. No invented facts, no synthesis beyond what the child entries support.

Scope boundary (explicit)

This skill does not implement:

• Fold-of-folds / hierarchical level stacking (DragonScale spec calls for it; deferred to a future skill).
• Automatic triggering (folds are always human-invoked in Phase 1).
• Semantic-tiling dedup (Mechanism 3; separate skill).

It does implement:

• Flat fold over raw log.md entries at a chosen batch exponent k.
• Structural idempotency via a deterministic fold ID.
• Extractive summarization with count-checking.

When referring to level in frontmatter, use batch_exponent: k (not level: k), because this skill does not produce hierarchical levels.

Modes

Why stdout-only in dry-run: the repo's hooks/hooks.json PostToolUse hook fires on any Write|Edit and runs git add wiki/ .raw/. Writing to /tmp does not stage /tmp, but it still triggers the hook, which will commit any pending wiki changes under a generic message. Dry-run must leave zero residue. Bash stdout does not fire the hook.

Concurrency (v1.7+)

The fold-page write in commit mode MUST be preceded by wiki-lock acquire:

FOLD_PATH="wiki/folds/${FOLD_ID}.md"
bash scripts/wiki-lock.sh acquire "$FOLD_PATH" || {
  echo "FAIL: another writer holds $FOLD_PATH; aborting fold."; exit 75
}
# … write the fold via Write/Edit (which fires the PostToolUse hook) …
bash scripts/wiki-lock.sh release "$FOLD_PATH"

Fold pages are deterministically named (fold-k{K}-from-{DATE}-to-{DATE}-n{COUNT}.md), so two parallel folds with the same parameters target the same path. Without the lock, they could overwrite each other's outputs. The duplicate-detection check inside this skill (already documented below) handles the "fold already exists" case at the SKILL level; the lock handles the in-flight-write race at the OS level.

Dry-run mode does not acquire a lock (no writes happen).

See skills/wiki-ingest/SKILL.md §Concurrency for the full lock semantics.

Deterministic fold ID

Every fold has an ID derived from its inputs:

fold-k{K}-from-{EARLIEST-DATE}-to-{LATEST-DATE}-n{COUNT}

Example: fold-k3-from-2026-04-10-to-2026-04-23-n8.

The filename in commit mode is wiki/folds/{FOLD-ID}.md. No date-of-creation in the filename. No timestamp in the title.

Duplicate detection (required): before emitting any output, check if wiki/folds/{FOLD-ID}.md already exists. If so, report "Fold already exists at wiki/folds/{FOLD-ID}.md. Use --force to overwrite, or pick a different range." and stop. This is the no-op idempotency guarantee; byte-identical content is NOT guaranteed (LLM prose varies) but the filename and scope are.

Parameters

• k (default 4): batch exponent. Batch size = 2^k. Typical values: k=3 (8), k=4 (16), k=5 (32).
• range (optional): explicit entry range entries 1-16. Overrides k.
• --force: overwrite an existing fold with the same ID. Default no.
• --commit: write to wiki/. Without it, dry-run stdout-only.

If fewer than 2^k log entries exist, report the shortfall and stop. Do not silently fold a partial batch.

Procedure

1. Parse log entries

grep -n "^## \[" wiki/log.md | head -{2^k}

Record for each entry: line number, date, operation, title, and the following bullet lines until the next ## [ or end-of-section.

2. Extract child page identifiers

From each entry's bullet list, extract:

• Location: wiki/path/to/page.md (the primary page)
• [[Wikilinks]] inline
• Pages created: and Pages updated: lists

Build a structured children list:

children:
  - date: "2026-04-23"
    op: "save"
    title: "DragonScale Memory v0.2 — post-adversarial-review"
    page: "[[DragonScale Memory]]"
  - ...

One record per log entry. Do not dedupe by page: if two entries both point to [[DragonScale Memory]], both records appear, distinguishable by date and title.

3. Read referenced pages (bounded)

Read only the pages that are not already captured fully in the log entry's bullets. Budget: 0-10 page reads. Hard ceiling: 15. If an entry's referenced page is missing, record page_missing: true and proceed.

4. Extractive summarization with count checks

Write the fold body per references/fold-template.md. Rules:

• Extractive only. Every outcome bullet and theme bullet must cite a specific child entry (e.g., (from 2026-04-14 session)) or a quoted line from that entry. Do not introduce events, counts, or interpretations not present in a child entry.
• Log entry is the primary source. If the log entry's bullets and the referenced meta-page disagree on a fact (e.g., a count), prefer the log-entry bullets and flag the mismatch as "source mismatch: log says X, meta says Y."
• Count checks. If you write "N concept pages" or "M repos updated," grep the source entries for the number and verify. Numeric mismatches are dry-run blockers.
• No merging across entries without naming them. A theme that spans multiple entries must name each contributing entry inline.
• Uncertainty is a feature. If an entry is ambiguous, say "ambiguous in source: [[Entry]]" rather than picking one interpretation.

5. Self-check before emitting

Before printing output, verify:

• Every child in children: frontmatter appears exactly once in the Child Entries table.
• Every entry in the table appears in the children: frontmatter.
• Every numeric claim in Key Outcomes is grep-verifiable against a child entry.
• The fold ID is deterministic and the file does not already exist (or --force is set).

If any check fails, abort and report the specific failure.

6. Emit

Dry-run: use Bash cat <<'EOF' ... EOF to stdout. Do not use Write. Print the fold ID and a one-line summary of what the commit step would do.

Commit (only after user says "commit the fold"):

1. Write the fold page to wiki/folds/{FOLD-ID}.md. (PostToolUse hook will auto-commit this.)
2. Edit wiki/index.md to add the fold link under a ## Folds section (create section if missing). (Hook auto-commits.)
3. Edit wiki/log.md to prepend one entry:

   ## [YYYY-MM-DD] fold | batch-exponent-k{K} rollup of N entries
   - Location: wiki/folds/{FOLD-ID}.md
   - Range: {EARLIEST-DATE} to {LATEST-DATE}
   - Children: N log entries
   

   (Hook auto-commits.)

Three auto-commits result. The user sees three separate wiki: auto-commit entries in git log. This is expected; do not attempt to suppress the hook.

Output schema

See references/fold-template.md for the canonical frontmatter and body layout.

Invariants

1. Structural idempotency: same range + same k → same fold ID → duplicate detection prevents double-writes. LLM prose may vary across runs; the location and scope are fixed.
2. Additive: children are never modified.
3. Bounded reads: 0-15 child-page reads per fold.
4. Extractive: zero invented facts. Count checks enforced.
5. No chaining: wiki-fold does not invoke wiki-lint, wiki-ingest, autoresearch, or save.