# RCA-01 · Superseded handbook sections served after a re-index

*Specimen: real structure, dummy content. The product, the incident and every number on this page are
invented to show how an RCA and its retrospective entry are written. † marks a dummy value.*

**Header block:** product · *Library staff assistant* · RCA-01 · 2026-05-30† · written by: the session ·
reviewed by: product owner · related: sign-off log item IS-02, risk register R-01

## 1 · What happened
On 2026-05-28† the policy team published handbook version 2026-06†, which moved the fines policy from
§6 to §7. The re-index ran and reported success. The next day's end-to-end test found that 3† questions
about fines were answered from the old §6, with a citation that resolved, because the old section was
still in the index. No patron was given a wrong answer: the assistant was on staging only.

## 2 · Root causes
1. The re-index added new sections and never removed sections that no longer existed.
2. "Re-index succeeded" meant "every new section was written", not "the index matches the handbook".
3. The citation check confirmed that a cited section **exists in the index**, not that it exists in the
   **current version** of the handbook.

## 3 · Why it was not caught earlier
- Every handbook update before this one only added sections; none moved or removed one.
- The eval set E-CIT was written against one handbook version and never re-run after a re-index.

## 4 · Preventions
| Prevention | Where it lives | Owner (role) | Done |
|---|---|---|---|
| Re-index replaces the whole index for a version; never appends | Re-index script | Tech lead | 2026-05-31† |
| A check compares the section list in the index with the handbook's contents page; a difference fails the run | Exit check of any re-index | Tech lead | 2026-05-31† |
| Citation validity is checked against the current version, not the index | Gate script | Tech lead | 2026-06-02† |
| E-CIT is re-run after every re-index | Phase spec template | Product manager | 2026-06-02† |

## 5 · What was not found
- No sign that any other policy area was affected: the section comparison found only the three† fines
  sections.
- No cause in the model or the retrieval ranking; both behaved as specified on the index they were given.

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# Retrospective · entry for RCA-01

| Field | Entry |
|---|---|
| Scenario | A handbook update moved a section; the re-index kept the old one |
| Risk | Staff repeat a superseded policy with a citation that looks valid (R-01) |
| Root cause | The re-index appended and never removed; "success" did not mean "matches the handbook" |
| Fix | Replace the index per version; compare sections with the contents page |
| Prevention | Citation check against the current version; E-CIT re-run after every re-index |
| Source | RCA-01 (this page). The retrospective summarises and points; it does not repeat the RCA |

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*What is real here: what happened stated before any cause; numbered root causes; a separate answer to
why it was not caught; preventions with a place, an owner and a date; what was looked for and not
found; and a retrospective entry that points to the RCA instead of copying it. Everything inside the
sections is invented.*