diff --git a/docs/JOURNAL.md b/docs/JOURNAL.md
index b2ed7fb..ffab266 100644
--- a/docs/JOURNAL.md
+++ b/docs/JOURNAL.md
@@ -12200,3 +12200,75 @@ Observation, not debt: `crates/ailang-codegen/src/drop.rs:379` has
 a `matches!(name.as_str(), "Str")` single-element check (not the
 4-set) — distinct invariant (heap-string-only semantics), out of
 scope for this consolidation.
+
+## 2026-05-10 — Iteration 22-tidy.5: strict duplicate-clause detection in fn/const/data parsers
+
+Closing the second milestone-22 carried-debt item flagged in
+`2026-05-09 — Iteration 22-tidy`: the strict duplicate-clause
+detection that 22b.4a introduced for `parse_class` /
+`parse_instance` / their method sub-parsers (10 sites) was missing
+from the sibling parsers `parse_fn`, `parse_const`, `parse_data` —
+those silently last-wins on duplicate clauses. This iteration
+lifts the strict pattern to those three siblings.
+
+Sites promoted to strict (8 total):
+
+- `parse_fn`: `doc`, `type`, `params`, `body`
+- `parse_const`: `doc`, `type`, `body`
+- `parse_data`: `doc` (only — `ctor` is multi-instance,
+  `drop-iterative` was already strict from Iter 18e)
+
+Each new strict check uses the established 22b.4a pattern
+(`if X.is_some() { return ParseError::Production { … } }`) and
+the established message form
+(`` "<prod> `<name>` has duplicate `(<clause> ...)` clause" ``).
+Eight new RED-first unit tests in `parse.rs::mod tests` pin each
+diagnostic.
+
+Mid-iter fixture correction (Task 2): the planned `parse_const`
+body fixtures used `(body (lit (int 42)))`, but bare integer
+literals in the surface are tokenised directly (`Tok::Int`), not
+as a `(lit (int N))` term. Implementer substituted bare integer
+literals (`(body 42)`, etc.) — preserves the load-bearing
+duplicate-clause assertion.
+
+Mid-iter fixup (Task 2 review): Task 1 originally added
+`/// Iter 22-tidy.5: …` rationale doc-comments to the four
+`parse_fn` tests, but Task 2 omitted them per CLAUDE.md comment
+policy ("Don't reference the current task, fix, or callers").
+For consistency, the iter-tag doc-comments were stripped from
+Task 1's tests in commit `9097b88`.
+
+Tasks (commit subjects):
+
+- 22-tidy.5.1: parse_fn rejects duplicate doc/type/params/body clauses
+- 22-tidy.5.2: parse_const rejects duplicate doc/type/body clauses
+- 22-tidy.5.2: drop transient iter-tags from parse_fn duplicate-clause tests
+- 22-tidy.5.3: parse_data rejects duplicate doc clause
+
+Acceptance: 8 new tests RED-first then GREEN; full workspace test
+sweep green (`cargo test --workspace` 0 FAILED across 23 test
+binaries); bench gates 0/0/0; no behaviour change for valid
+fixtures (the round-trip suite stays green). The strict-vs-loose
+asymmetry between class/instance and fn/const/data parsers is
+retired.
+
+Observation (out-of-scope, queued): the duplicate-clause check
+pattern now appears at 18 sites across the parser (10 from 22b.4a
++ 8 from this iter). A `check_clause_unique!` macro or
+`fn duplicate_clause_err(production, name, clause, pos)` helper
+would consolidate them. Quality reviewer flagged as Nit during
+Task 1 review; left for a future iter. Three similar lines beats
+a premature abstraction; eighteen similar blocks may be the
+tipping point. Re-evaluate next time the strict pattern needs
+extending.
+
+Carried-debt status (after this iter):
+
+- ✅ Primitive-name-set consolidation (closed 22-tidy.4).
+- ✅ Strict duplicate-clause detection in fn/const/data (this iter).
+- ⏳ Form-B (prose) printer arms for ClassDef / InstanceDef — still
+  queued.
+- ✅ Lib.rs gap-related sites at lib.rs:1266 / 1853-1856 / 1978 /
+  2314-2316 — audit confirmed defensive (no action needed; see
+  `2026-05-10 — Audit: mono-pass env-seeding gaps`).