@@ -259,25 +259,23 @@ export function packagelessOverlayWriteRefusal(
     const sole = pairs.length === 1 ? pairs[0]! : undefined;
     // One base: its pair, by name. Several: the pair of the base the writer
     // customizes, each named — never guessed (the ceremony lists such a row).
-    const into = sole
-        ? `'${sole.pair}' (?package=${sole.pair})`
-        : `the pair of the package it customizes (${pairs.map((p) => `'${p.pair}'`).join(' or ')}, as ?package=<that pair>)`;
+    const pair = sole ? `'${sole.pair}' (?package=${sole.pair})` : `the pair of the package it customizes (${pairs.map((p) => `'${p.pair}'`).join(' or ')})`;
     const declared = sole ? `overrides: { package: '${sole.base}', basedOn }` : 'overrides: { package: <that base>, basedOn }';
+    // The fix first, then the rule and the ceremony: the REST door bounds a
+    // refusal's text (`CLIENT_MESSAGE_MAX`, 500 characters, `@objectstack/types`),
+    // and Setup shows that text as sent.
     const ceremony = sole
-        ? 'A package-less customization stored before this release is still served; run '
-            + `\`os migrate packageless-overlays\` first to move it into '${sole.pair}'.`
-        : 'A package-less customization stored before this release is still served; run '
-            + '`os migrate packageless-overlays` first: it lists a name several packages ship for you to place.';
-    const fix = operation === 'delete'
-        ? `Remove it from ${into}. ${ceremony}`
-        : operation === 'rollback'
-            ? `Its customization belongs in ${into}: run \`os migrate packageless-overlays\` to move the row there, then roll it back.`
-            : `${operation === 'publish' ? 'Publish' : 'Save'} it into ${into}, declaring ${declared}. ${ceremony}`;
-    const what = operation === 'rollback' ? 'a rollback of its package-less row' : 'a write naming no package';
-    const err = new Error(
-        `${item} ${shipped}, and ${what} onto a packaged item is closed: a customization of an installed package `
-        + `lives in its paired .custom package (ADR-0146 D11). ${fix}`,
-    );
+        ? `\`os migrate packageless-overlays\` moves it into '${sole.pair}'`
+        : '`os migrate packageless-overlays` lists it for you to place';
+    const closed = 'A write naming no package onto a packaged item is closed (ADR-0146 D11); '
+        + `a package-less customization stored before it is still served until ${ceremony}.`;
+    const message = operation === 'rollback'
+        ? `${item} ${shipped}, and a rollback of its package-less row is closed (ADR-0146 D11): run `
+            + `\`os migrate packageless-overlays\` to move the row into ${pair}, then roll it back there.`
+        : operation === 'delete'
+            ? `${item} ${shipped}: remove its customization from ${pair}. ${closed}`
+            : `${item} ${shipped}: ${operation === 'publish' ? 'publish' : 'save'} it into ${pair}, declaring ${declared}. ${closed}`;
+    const err = new Error(message);
     (err as any).code = 'NOT_OVERRIDABLE';
     (err as any).status = 403;
     return err;
 
@@ -426,6 +426,10 @@ describe('an item a CODE package ships: the package-less write is closed (ADR-01
         expect(resolveThrownHttpError(e)).toMatchObject({ status: 403, code: 'NOT_OVERRIDABLE' });
         expect(String((e as Error).message)).toContain(`'${PAIR}'`);
         expect(String((e as Error).message)).toContain('os migrate packageless-overlays');
+        // The REST door cuts a refusal's text at 500 characters
+        // (`CLIENT_MESSAGE_MAX`, `@objectstack/types`), and Setup shows it as
+        // sent: the whole sentence fits, the ceremony included.
+        expect(String((e as Error).message).length).toBeLessThan(500);
     };
 
     it('with no stored row: the package-less save is refused naming the pair, and nothing is written', async () => {
 
@@ -41,16 +41,13 @@ const PAIR = `${BASE}.custom`;
 const doc = (content: string) => ({ name: NAME, label: NAME, content, group: 'reference' });
 
 /** The server's sentences, worded as the framework words them; read back verbatim below. */
+const CLOSED =
+  'A write naming no package onto a packaged item is closed (ADR-0146 D11); a package-less customization stored ' +
+  `before it is still served until \`os migrate packageless-overlays\` moves it into '${PAIR}'.`;
 const SAVE_CLOSED =
-  `'doc/${NAME}' ships in '${BASE}', and a write naming no package onto a packaged item is closed: a customization ` +
-  `of an installed package lives in its paired .custom package (ADR-0146 D11). Save it into '${PAIR}' ` +
-  `(?package=${PAIR}), declaring overrides: { package: '${BASE}', basedOn }. A package-less customization stored ` +
-  `before this release is still served; run \`os migrate packageless-overlays\` first to move it into '${PAIR}'.`;
-const RESET_CLOSED =
-  `'doc/${NAME}' ships in '${BASE}', and a write naming no package onto a packaged item is closed: a customization ` +
-  `of an installed package lives in its paired .custom package (ADR-0146 D11). Remove it from '${PAIR}' ` +
-  `(?package=${PAIR}). A package-less customization stored before this release is still served; run ` +
-  `\`os migrate packageless-overlays\` first to move it into '${PAIR}'.`;
+  `'doc/${NAME}' ships in '${BASE}': save it into '${PAIR}' (?package=${PAIR}), declaring ` +
+  `overrides: { package: '${BASE}', basedOn }. ${CLOSED}`;
+const RESET_CLOSED = `'doc/${NAME}' ships in '${BASE}': remove its customization from '${PAIR}' (?package=${PAIR}). ${CLOSED}`;
 
 const server = {
   /** The packaged item's stored package-less row, as an unmigrated deployment holds it. */