iroha: history

Show the evolution of a decision, not just its current state. iroha never overwrites a decision when the project changes its mind: the old row stays as Status=Superseded and the new one links back to it via Supersedes. This skill follows that chain so you can read the story — what was chosen first, what replaced it, and the reason at each turn. Read-only; it never writes. Report in the user's conversation language.

1. Preconditions

L="${CLAUDE_PLUGIN_ROOT}/scripts/_lib/config.ts"; IDX="${CLAUDE_PLUGIN_ROOT}/scripts/_lib/index.ts"
SEARCH="${CLAUDE_PLUGIN_ROOT}/scripts/_lib/search.ts"; ROOT="$PWD"
bun "$L" get decisions_ds_id    # empty -> tell the user to run /iroha:init, then stop

If decisions_ds_id is empty, tell the user to run /iroha:init and stop.

2. Resolve the topic to a chain head (the current Active decision)

The lineage is walked from the most recent decision on the topic (usually the Active one) back to the original. Find that head from $ARGUMENTS:

# a) Exact-ish topic match (the "<topic>:" prefix is the dedup key).
bun "$IDX" find-topic "$ROOT" "$ARGUMENTS"
# b) Fuzzy fallback when the user typed a paraphrase, not the literal topic.
bun "$SEARCH" "$ROOT" "$ARGUMENTS" decision 5 0

Pick the head:

• Prefer a row with status="Active" whose topic (or title) matches the query.
• If several topics match, list them and ask which lineage to trace (do not guess).
• If nothing matches, say so honestly ("no decision recorded for <topic>") and stop — never invent

a chain.

3. Walk the lineage (offline, from the local index)

bun "$IDX" chain "$ROOT" "<head-id>"   # newest first: head, predecessor, …, original

Each line is a decision record {id, topic, status, date, title, supersedes, text}. A chain of length 1 means the decision has no predecessor — say "this decision has no earlier version" rather than padding it.

4. Deepen with the canonical reason (Notion is the source of truth)

The index text is only a short search snippet. For the actual Rationale and rejected Alternatives at each step, fetch the full pages (the index has no content):

# for each id in the chain (cap at ~6 to stay cheap):
#   notion-fetch <id>   -> read Name / Rationale / Alternatives / Date / Session

Use the Notion MCP notion-fetch tool with each chain id. If a fetch fails or Notion is unreachable, fall back to the index text snippet and say it is a summary, not the full rationale.

5. Present the evolution (newest → oldest)

Render the chain as a short narrative, current decision first, each step annotated with why it changed (drawn from the newer decision's Rationale — a supersede almost always states what the predecessor got wrong):

Topic: リコール  (3 decisions, current is Active)

▸ NOW  リコール: hybrid(検索+index)        Active      2026-06-25
       Why: notion-search is top-N + write-lag; a keys-only local index enumerates everything …
   ↑ replaced
   リコール: notion-search 主体             Superseded  2026-06-25
       Why it was dropped: search alone misses freshly-saved rows (write-lag) …
   ↑ replaced
   リコール: ローカル grep                  Superseded  2026-06-24
       (original)  query-database-view 400s on the free plan, so local grep …

Keep it tight: the choice, the date, the one-line reason, and the supersede arrows. Link each decision's Notion URL (https://www.notion.so/<bare-id>) so the user can open the full page.

Notes

• Lineage is URL-linked, not a Notion relation. Each decision's Supersedes is a URL to its

predecessor (the same pattern as the Session↔Decision link), chosen to dodge the MCP relation- write bug. The local index mirrors the same edge as a supersedes id so the walk is offline.

• Only forward-populated chains are complete. save-session links every new supersession going

forward; older chains were backfilled only where the predecessor was stated unambiguously. If a Superseded decision has no supersedes and no successor links to it, its lineage is unknown — say so rather than guessing a predecessor.

• This skill is read-only. Repairing a missing/incorrect link is /iroha:audit's job (a

reversible edit), not history's.