diff --git a/src/agents/tools/common.ts b/src/agents/tools/common.ts
index 22e271b7ccd6..9bcab8a49cec 100644
--- a/src/agents/tools/common.ts
+++ b/src/agents/tools/common.ts
@@ -1,8 +1,12 @@
 import type { TSchema } from "typebox";
 import { readLocalFileSafely } from "../../infra/fs-safe.js";
-import { parseStrictFiniteNumber } from "../../infra/parse-finite-number.js";
 import { detectMime } from "../../media/mime.js";
 import { readSnakeCaseParamRaw } from "../../param-key.js";
+import {
+  asPositiveSafeInteger,
+  asSafeIntegerInRange,
+  parseStrictFiniteNumber,
+} from "../../shared/number-coercion.js";
 import { normalizeStringEntries } from "../../shared/string-normalization.js";
 import type { ImageSanitizationLimits } from "../image-sanitization.js";
 import type { AgentTool, AgentToolResult, AgentToolUpdateCallback } from "../runtime/index.js";
@@ -194,10 +198,10 @@ export function readNumberParam(
     return undefined;
   }
   if (positiveInteger) {
-    return Number.isSafeInteger(value) && value > 0 ? value : undefined;
+    return asPositiveSafeInteger(value);
   }
   if (nonNegativeInteger) {
-    return Number.isSafeInteger(value) && value >= 0 ? value : undefined;
+    return asSafeIntegerInRange(value, { min: 0 });
   }
   return integer ? Math.trunc(value) : value;
 }
diff --git a/src/infra/parse-finite-number.ts b/src/infra/parse-finite-number.ts
index 6084559708fc..29e990245405 100644
--- a/src/infra/parse-finite-number.ts
+++ b/src/infra/parse-finite-number.ts
@@ -1,54 +1,7 @@
-function normalizeNumericString(value: string): string | undefined {
-  const trimmed = value.trim();
-  return trimmed ? trimmed : undefined;
-}
-
-export function parseFiniteNumber(value: unknown): number | undefined {
-  if (typeof value === "number" && Number.isFinite(value)) {
-    return value;
-  }
-  if (typeof value === "string") {
-    return parseStrictFiniteNumber(value);
-  }
-  return undefined;
-}
-
-export function parseStrictInteger(value: unknown): number | undefined {
-  if (typeof value === "number") {
-    return Number.isSafeInteger(value) ? value : undefined;
-  }
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const normalized = normalizeNumericString(value);
-  if (!normalized || !/^[+-]?\d+$/.test(normalized)) {
-    return undefined;
-  }
-  const parsed = Number(normalized);
-  return Number.isSafeInteger(parsed) ? parsed : undefined;
-}
-
-export function parseStrictFiniteNumber(value: unknown): number | undefined {
-  if (typeof value === "number") {
-    return Number.isFinite(value) ? value : undefined;
-  }
-  if (typeof value !== "string") {
-    return undefined;
-  }
-  const normalized = normalizeNumericString(value);
-  if (!normalized || !/^[+-]?(?:(?:\d+\.?\d*)|(?:\.\d+))(?:e[+-]?\d+)?$/i.test(normalized)) {
-    return undefined;
-  }
-  const parsed = Number(normalized);
-  return Number.isFinite(parsed) ? parsed : undefined;
-}
-
-export function parseStrictPositiveInteger(value: unknown): number | undefined {
-  const parsed = parseStrictInteger(value);
-  return parsed !== undefined && parsed > 0 ? parsed : undefined;
-}
-
-export function parseStrictNonNegativeInteger(value: unknown): number | undefined {
-  const parsed = parseStrictInteger(value);
-  return parsed !== undefined && parsed >= 0 ? parsed : undefined;
-}
+export {
+  parseFiniteNumber,
+  parseStrictFiniteNumber,
+  parseStrictInteger,
+  parseStrictNonNegativeInteger,
+  parseStrictPositiveInteger,
+} from "../shared/number-coercion.js";
diff --git a/src/plugin-sdk/number-runtime.ts b/src/plugin-sdk/number-runtime.ts
index 5f34108baee7..e3bb9d85ced3 100644
--- a/src/plugin-sdk/number-runtime.ts
+++ b/src/plugin-sdk/number-runtime.ts
@@ -6,4 +6,4 @@ export {
   parseStrictFiniteNumber,
   parseStrictNonNegativeInteger,
   parseStrictPositiveInteger,
-} from "../infra/parse-finite-number.js";
+} from "../shared/number-coercion.js";
diff --git a/src/plugin-sdk/string-coerce-runtime.ts b/src/plugin-sdk/string-coerce-runtime.ts
index 311f5c06642f..b7299319497f 100644
--- a/src/plugin-sdk/string-coerce-runtime.ts
+++ b/src/plugin-sdk/string-coerce-runtime.ts
@@ -20,6 +20,10 @@ export {
   asPositiveSafeInteger,
   asSafeIntegerInRange,
   parseFiniteNumber,
+  parseStrictFiniteNumber,
+  parseStrictInteger,
+  parseStrictNonNegativeInteger,
+  parseStrictPositiveInteger,
 } from "../shared/number-coercion.js";
 export { asBoolean, parseBooleanValue } from "../utils/boolean.js";
 export {
diff --git a/src/shared/number-coercion.test.ts b/src/shared/number-coercion.test.ts
index 297fc80007d7..1e7a5d185092 100644
--- a/src/shared/number-coercion.test.ts
+++ b/src/shared/number-coercion.test.ts
@@ -4,6 +4,10 @@ import {
   asFiniteNumberInRange,
   asSafeIntegerInRange,
   parseFiniteNumber,
+  parseStrictFiniteNumber,
+  parseStrictInteger,
+  parseStrictNonNegativeInteger,
+  parseStrictPositiveInteger,
 } from "./number-coercion.js";
 
 describe("number-coercion", () => {
@@ -37,4 +41,28 @@ describe("number-coercion", () => {
     expect(parseFiniteNumber("")).toBeUndefined();
     expect(parseFiniteNumber("nope")).toBeUndefined();
   });
+
+  test("parseStrictInteger accepts only safe integer tokens", () => {
+    expect(parseStrictInteger("42")).toBe(42);
+    expect(parseStrictInteger(" -7 ")).toBe(-7);
+    expect(parseStrictInteger("+9")).toBe(9);
+    expect(parseStrictInteger("1.5")).toBeUndefined();
+    expect(parseStrictInteger("1e3")).toBeUndefined();
+    expect(parseStrictInteger(Number.MAX_SAFE_INTEGER + 1)).toBeUndefined();
+  });
+
+  test("parseStrictFiniteNumber rejects partial numeric strings", () => {
+    expect(parseStrictFiniteNumber("42")).toBe(42);
+    expect(parseStrictFiniteNumber(".5")).toBe(0.5);
+    expect(parseStrictFiniteNumber("1e3")).toBe(1000);
+    expect(parseStrictFiniteNumber("3.14ms")).toBeUndefined();
+    expect(parseStrictFiniteNumber("0x10")).toBeUndefined();
+  });
+
+  test("strict integer range helpers enforce sign", () => {
+    expect(parseStrictPositiveInteger("9")).toBe(9);
+    expect(parseStrictPositiveInteger("0")).toBeUndefined();
+    expect(parseStrictNonNegativeInteger("0")).toBe(0);
+    expect(parseStrictNonNegativeInteger("-1")).toBeUndefined();
+  });
 });
diff --git a/src/shared/number-coercion.ts b/src/shared/number-coercion.ts
index 1a2025fc9e4d..c886a053dab9 100644
--- a/src/shared/number-coercion.ts
+++ b/src/shared/number-coercion.ts
@@ -47,21 +47,58 @@ export function asSafeIntegerInRange(
   return value;
 }
 
+function normalizeNumericString(value: string): string | undefined {
+  const trimmed = value.trim();
+  return trimmed ? trimmed : undefined;
+}
+
 export function parseFiniteNumber(value: unknown): number | undefined {
+  if (typeof value === "number") {
+    return Number.isFinite(value) ? value : undefined;
+  }
+  return parseStrictFiniteNumber(value);
+}
+
+export function parseStrictInteger(value: unknown): number | undefined {
+  if (typeof value === "number") {
+    return Number.isSafeInteger(value) ? value : undefined;
+  }
+  if (typeof value !== "string") {
+    return undefined;
+  }
+  const normalized = normalizeNumericString(value);
+  if (!normalized || !/^[+-]?\d+$/.test(normalized)) {
+    return undefined;
+  }
+  const parsed = Number(normalized);
+  return Number.isSafeInteger(parsed) ? parsed : undefined;
+}
+
+export function parseStrictFiniteNumber(value: unknown): number | undefined {
   if (typeof value === "number") {
     return Number.isFinite(value) ? value : undefined;
   }
   if (typeof value !== "string") {
     return undefined;
   }
-  const trimmed = value.trim();
-  if (!trimmed || !/^[+-]?(?:(?:\d+\.?\d*)|(?:\.\d+))(?:e[+-]?\d+)?$/i.test(trimmed)) {
+  const normalized = normalizeNumericString(value);
+  if (!normalized || !/^[+-]?(?:(?:\d+\.?\d*)|(?:\.\d+))(?:e[+-]?\d+)?$/i.test(normalized)) {
     return undefined;
   }
-  const parsed = Number(trimmed);
+  const parsed = Number(normalized);
   return Number.isFinite(parsed) ? parsed : undefined;
 }
 
 export function asPositiveSafeInteger(value: unknown): number | undefined {
   return typeof value === "number" && Number.isSafeInteger(value) && value > 0 ? value : undefined;
 }
+
+export function parseStrictPositiveInteger(value: unknown): number | undefined {
+  const parsed = parseStrictInteger(value);
+  return parsed !== undefined && parsed > 0 ? parsed : undefined;
+}
+
+export function parseStrictNonNegativeInteger(value: unknown): number | undefined {
+  const parsed = parseStrictInteger(value);
+  return parsed !== undefined && parsed >= 0 ? parsed : undefined;
+}