diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 7e1970768..e66800fd5 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -73,6 +73,8 @@ Windows/Claude Desktop Cowork confirmation remains outstanding (#927).
 
 ## Tools and local MCP server — October 1, 2026
 
+Tool argument string lengths follow JSON Schema Unicode code-point counts, so supplementary characters count once rather than as two UTF-16 units.
+
 `gods-eye-view/tools` defines queries that answer questions from the app's data,
 and `gods-eye-view/tools/mcp` exposes a composed catalog over the Model Context
 Protocol. `npm run mcp` serves Core's tools over stdio to a local MCP client,
@@ -5310,8 +5312,3 @@ datacenters, dams and the Nepal locator retain that shared credit while displaye
 
 Military fragments stitch by source identity. Different mapped parcels merge only
 when their footprints touch or contain one another, never across a seam tolerance gap.
-
-
-### fix(tools): enforce string schema lengths by Unicode code point
-
-Count code points for minLength and maxLength, preserving ASCII behavior and regular-expression validation.
diff --git a/src/tools/schema.js b/src/tools/schema.js
index cdb63cfc1..b6e8e2fd0 100644
--- a/src/tools/schema.js
+++ b/src/tools/schema.js
@@ -106,7 +106,8 @@ export function validateValue(schema, value, path = 'arguments') {
         fail('must be a string');
         break;
       }
-      const length = [...value].length;
+      let length = 0;
+      for (const character of value) length += 1;
       if (schema.minLength != null && length < schema.minLength)
         fail(`must be at least ${schema.minLength} characters`);
       if (schema.maxLength != null && length > schema.maxLength)