diff --git a/scripts/check-skills-token-ratchet.mjs b/scripts/check-skills-token-ratchet.mjs
index 23d1d47c0a..187be7f406 100644
--- a/scripts/check-skills-token-ratchet.mjs
+++ b/scripts/check-skills-token-ratchet.mjs
@@ -166,7 +166,13 @@ export const CEILINGS = new Map([
   // CEILING_BASIS.strippedInternalIds. `(was N)` is the ceiling this replaced.
   ['skills/objectstack-ai/SKILL.md', 6806], //          -18 (was 6824)
   ['skills/objectstack-api/SKILL.md', 6331], //         -11 (was 6342)
-  ['skills/objectstack-automation/SKILL.md', 12511], // -32 (was 12543)
+  // 12511 -> 12643 (#11348): the flow value-expression section documented the
+  // expression surface but not the function vocabulary (round/floor/ceil/abs/
+  // min/max); an unknown function fails at RUNTIME, not at flow-save, so the
+  // published teaching is the only guard. +132 tokens, compressed to minimum.
+  // Maintainer ruling 2026-08-25 (option B1, raise the ceiling), verbatim and
+  // untranslated: 「我看到了,你分析过了,接受你的建议」.
+  ['skills/objectstack-automation/SKILL.md', 12643],
   ['skills/objectstack-data/SKILL.md', 13783], //       -34 (was 13817)
   ['skills/objectstack-formula/SKILL.md', 6002], //     -53 (was 6055)
   ['skills/objectstack-i18n/SKILL.md', 6338], //        -11 (was 6349)
diff --git a/skills/objectstack-automation/SKILL.md b/skills/objectstack-automation/SKILL.md
index 0d00cf9cdc..7979b4eb04 100644
--- a/skills/objectstack-automation/SKILL.md
+++ b/skills/objectstack-automation/SKILL.md
@@ -839,11 +839,18 @@ them right the first time:
    - `{var}` / `{record.title}` — variable / record field
    - `{record.tags.0}` — **array index** (e.g. a `multiple: true` lookup, stored as an array)
    - `{$User.Id}` / `{NOW()}` / `{TODAY() + 30}` — current user / date macros
+   - `{round(x)}` `{floor(x)}` `{ceil(x)}` `{abs(x)}` `{min(a,b)}` `{max(a,b)}` —
+     mirror the CEL stdlib 1:1. `round` is **integer-only** (no `round(x, 2)`);
+     for N decimals write `{round(x * 100) / 100}` (scale 2)
    - anything without `{…}` is a **literal**
 
    ❌ `body: '{{ai_reply}}'` — double-brace is the *formula / template-field* dialect, **not** flow values
    ❌ `ticket: '$source.id'` — a bare `$ref` is a literal string, not interpolated
    ✅ `body: '{ai_reply}'`, `ticket: '{source.id}'`
+   ❌ `'{ROUND(x, 2)}'` / `'{Math.round(x)}'` / `'{(x).toFixed(2)}'` — any other
+   name in call position **fails the node** with a named error naming the
+   supported set. The build does **not** catch these (conditions are checked,
+   value expressions are not) and a `fault` edge cannot route it.
 
 7. **`create_record`'s `outputVariable` holds the created RECORD, not its id.**
    Reference a field explicitly.