diff --git a/parser/typerecover.py b/parser/typerecover.py
index 5d4baa4..ded1806 100644
--- a/parser/typerecover.py
+++ b/parser/typerecover.py
@@ -184,3 +184,58 @@ def walk(o):
 
     walk(idl)
     return idl, fixed
+
+
+# Strip const/struct qualifiers and pointer stars to the bare base name.
+_BASE_RE = re.compile(r"\b(?:const|struct|volatile)\b|\*")
+
+
+def _base_name(t):
+    return _BASE_RE.sub(" ", t or "").strip()
+
+
+def normalize_canonical(idl):
+    """Re-derive each type slot's ``canonical`` from its ``cType`` typedef.
+
+    ``canonical`` is the MEOS/PG typedef the public API exposes (``_TYPE_MAP``),
+    not libclang's fully-resolved platform type. The self-contained (installed)
+    header parse resolves ``TimestampTz`` -> ``long`` and ``Jsonb *`` -> ``struct
+    varlena *`` while ``cType`` keeps the faithful typedef, so re-derive
+    ``canonical`` from ``cType`` -- a binding generator keys on ``canonical`` and
+    must see the semantic type (a timestamp, a jsonb), never its platform width.
+    Idempotent; a no-op on the source parse (``canonical`` already equals the
+    typedef) and on non-typedef slots (``Temporal *``, ``int *``). Complements
+    ``recover_collapsed_types``: that recovers a ``cType`` the preprocessor erased
+    to ``int``; this trusts a faithful ``cType`` and only re-spells ``canonical``.
+    """
+    fixed = 0
+
+    def want(ctype):
+        mapped = _TYPE_MAP.get(_base_name(ctype))
+        if not mapped:
+            return None
+        const = "const " if re.search(r"\bconst\b", ctype) else ""
+        stars = "".join(c for c in ctype if c == "*")
+        return f"{const}{mapped}{(' ' + stars) if stars else ''}"
+
+    def fix(slot):
+        nonlocal fixed
+        if not (isinstance(slot, dict) and "canonical" in slot):
+            return
+        ctype = slot.get("cType") or slot.get("c")
+        w = want(ctype) if ctype else None
+        if w and _nospace(slot["canonical"]) != _nospace(w):
+            slot["canonical"] = w
+            fixed += 1
+
+    def walk(o):
+        if isinstance(o, dict):
+            fix(o)
+            for v in o.values():
+                walk(v)
+        elif isinstance(o, list):
+            for v in o:
+                walk(v)
+
+    walk(idl)
+    return idl, fixed
diff --git a/run.py b/run.py
index ac607d5..d082a6b 100644
--- a/run.py
+++ b/run.py
@@ -7,7 +7,7 @@
 from parser.parser import parse_all_headers, merge_meta
 from parser.portable import attach_portable_aliases, classify_backing_sqlfn
 from parser.covering import attach_temporal_covering
-from parser.typerecover import recover_collapsed_types
+from parser.typerecover import recover_collapsed_types, normalize_canonical
 from parser.header_types import reconcile
 from parser.shapeinfer import infer_shapes
 from parser.nullable import merge_nullable
@@ -79,6 +79,17 @@ def main():
     #     recover_collapsed_types (H3Index/Quadbin -> uint64_t) are left intact.
     idl = reconcile(idl, HEADERS_DIR)
 
+    # 1d. Re-spell each slot's `canonical` as the MEOS typedef its `cType` names,
+    #     not libclang's platform resolution. The self-contained (installed)
+    #     header parse resolves TimestampTz -> long and Jsonb * -> varlena *; the
+    #     source parse leaves them as the typedef. Deriving canonical from the
+    #     faithful cType makes both parses agree, so a binding generator (which
+    #     keys on canonical) marshals timestamps/jsonb rather than dropping them.
+    idl, ncanon = normalize_canonical(idl)
+    if ncanon:
+        print(f"      normalized {ncanon} canonical spellings to the cType typedef",
+              file=sys.stderr)
+
     # 1d. Generate the codegen `shape` from the signatures + Doxygen, replacing
     #     the hand-maintained meta stub.  outputArrays/arrayReturn come from the
     #     parameter forms; nullable comes from the C `@param ... may be NULL` SoT.
diff --git a/tests/test_typerecover.py b/tests/test_typerecover.py
index 5304c88..00a0f0b 100644
--- a/tests/test_typerecover.py
+++ b/tests/test_typerecover.py
@@ -145,6 +145,26 @@ def test_cell_id_canonical_normalized_uniform(self):
             self.assertEqual(rt["c"], "uint64_t", f"{name} c")
             self.assertEqual(rt["canonical"], "uint64_t", f"{name} canonical")
 
+    def test_typedef_canonical_not_platform_resolved(self):
+        # ``canonical`` is the MEOS typedef its ``cType`` names, never libclang's
+        # fully-resolved platform type. On the self-contained (installed-header)
+        # parse ``TimestampTz`` resolves to ``long`` and ``Jsonb *`` / ``JsonPath
+        # *`` to ``varlena *`` while ``cType`` keeps the typedef; normalize_canonical
+        # re-derives ``canonical`` from the faithful ``cType`` so a binding
+        # generator (which keys on ``canonical``) marshals the semantic type
+        # instead of dropping the function — a guard on that pass.
+        def canon(name, pname):
+            self.assertIn(name, self.by_name, f"{name} missing from IDL")
+            p = next(p for p in self.by_name[name]["params"] if p["name"] == pname)
+            return (p["cType"], p["canonical"])
+        self.assertEqual(canon("tint_value_at_timestamptz", "t"),
+                         ("TimestampTz", "TimestampTz"))
+        if "jsonb_path_exists" in self.by_name:  # JSON=ON-conditional surface
+            self.assertEqual(canon("jsonb_path_exists", "jb"),
+                             ("const Jsonb *", "const Jsonb *"))
+            self.assertEqual(canon("jsonb_path_exists", "jp"),
+                             ("const JsonPath *", "const JsonPath *"))
+
     # ---- genuine-int controls (must NOT be rewritten) ----------------------
 
     def test_genuine_int_left_untouched(self):