diff --git a/skills/rig/rig.ts b/skills/rig/rig.ts
index f201a49..8650865 100644
--- a/skills/rig/rig.ts
+++ b/skills/rig/rig.ts
@@ -2652,6 +2652,13 @@ function describeSchemaType(schema: Schema): string {
     return `array of ${itemType}`;
   }
   if ("type" in schema) {
+    if ((schema as { type: string }).type === "string") {
+      const { minLength, format } = schema as StringSchema;
+      if (format === "uri") return "URL string";
+      if (format === "date") return "date string (YYYY-MM-DD)";
+      if (format === "path") return "path string";
+      if (minLength !== undefined && minLength > 0) return "non-empty string";
+    }
     return (schema as { type: string }).type;
   }
   if ("enum" in schema) {
diff --git a/src/rig.test.ts b/src/rig.test.ts
index 406cc18..a25c693 100644
--- a/src/rig.test.ts
+++ b/src/rig.test.ts
@@ -1962,4 +1962,48 @@ describe("missing required field error message", () => {
       expect(result.error.message).toContain("any");
     }
   });
+
+  it("reports a missing required s.nonEmptyString field as 'non-empty string'", () => {
+    const schema = s.object({ slug: s.nonEmptyString, name: s.string });
+    const result = analyzeResponse(JSON.stringify({ name: "x" }), schema, "test", 1);
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error.message).toContain("missing required field");
+      expect(result.error.message).toContain("$.slug");
+      expect(result.error.message).toContain("non-empty string");
+    }
+  });
+
+  it("reports a missing required s.url field as 'URL string'", () => {
+    const schema = s.object({ endpoint: s.url, name: s.string });
+    const result = analyzeResponse(JSON.stringify({ name: "x" }), schema, "test", 1);
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error.message).toContain("missing required field");
+      expect(result.error.message).toContain("$.endpoint");
+      expect(result.error.message).toContain("URL string");
+    }
+  });
+
+  it("reports a missing required s.date field as 'date string (YYYY-MM-DD)'", () => {
+    const schema = s.object({ createdAt: s.date, name: s.string });
+    const result = analyzeResponse(JSON.stringify({ name: "x" }), schema, "test", 1);
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error.message).toContain("missing required field");
+      expect(result.error.message).toContain("$.createdAt");
+      expect(result.error.message).toContain("date string (YYYY-MM-DD)");
+    }
+  });
+
+  it("reports a missing required s.path field as 'path string'", () => {
+    const schema = s.object({ filePath: s.path, name: s.string });
+    const result = analyzeResponse(JSON.stringify({ name: "x" }), schema, "test", 1);
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.error.message).toContain("missing required field");
+      expect(result.error.message).toContain("$.filePath");
+      expect(result.error.message).toContain("path string");
+    }
+  });
 });