diff --git a/docs/.generated/plugin-sdk-api-baseline.sha256 b/docs/.generated/plugin-sdk-api-baseline.sha256
index 74f2fe32dd0..a053924707b 100644
--- a/docs/.generated/plugin-sdk-api-baseline.sha256
+++ b/docs/.generated/plugin-sdk-api-baseline.sha256
@@ -1,2 +1,2 @@
-57289c57bab5188013ab1895d26acabada49aff864b3207f1a3ea3e1d92c7791  plugin-sdk-api-baseline.json
-445e5e72a321486831c2c936118302dbc2cde793f5e1dc5beab29100cae8150e  plugin-sdk-api-baseline.jsonl
+1805b1ddbd9036dac247b4eb01144c791e54e3a4826298bca4f85f67e936d8e2  plugin-sdk-api-baseline.json
+e1a4138ec4962ecb09472bf97cabebb98477d82af75f701142323706dcaa95f2  plugin-sdk-api-baseline.jsonl
diff --git a/extensions/file-transfer/src/shared/params.test.ts b/extensions/file-transfer/src/shared/params.test.ts
index 988c1940faa..18cc1f00ebe 100644
--- a/extensions/file-transfer/src/shared/params.test.ts
+++ b/extensions/file-transfer/src/shared/params.test.ts
@@ -1,8 +1,14 @@
 // File Transfer tests cover params plugin behavior.
 import { describe, expect, it } from "vitest";
-import { readClampedInt, readGatewayCallOptions } from "./params.js";
+import { humanSize, readClampedInt, readGatewayCallOptions } from "./params.js";
 
 describe("file-transfer shared params", () => {
+  it("preserves spaced binary-scaled transfer labels", () => {
+    expect(humanSize(512)).toBe("512 B");
+    expect(humanSize(1536)).toBe("1.5 KB");
+    expect(humanSize(2 * 1024 * 1024)).toBe("2.00 MB");
+  });
+
   it("normalizes string timeoutMs values for gateway calls", () => {
     expect(readGatewayCallOptions({ timeoutMs: "5000" }).timeoutMs).toBe(5000);
   });
diff --git a/extensions/file-transfer/src/shared/params.ts b/extensions/file-transfer/src/shared/params.ts
index c2563bd1431..db47f4f8a5c 100644
--- a/extensions/file-transfer/src/shared/params.ts
+++ b/extensions/file-transfer/src/shared/params.ts
@@ -1,6 +1,7 @@
 // Shared param-validation helpers used by all four agent tools.
 // Goal: identical validation behavior + identical error shapes everywhere.
 
+import { formatByteSize } from "openclaw/plugin-sdk/number-runtime";
 import { readPositiveIntegerParam } from "openclaw/plugin-sdk/param-readers";
 
 type GatewayCallOptions = {
@@ -50,11 +51,10 @@ export function readClampedInt(params: {
 }
 
 export function humanSize(bytes: number): string {
-  if (bytes < 1024) {
-    return `${bytes} B`;
-  }
-  if (bytes < 1024 * 1024) {
-    return `${(bytes / 1024).toFixed(1)} KB`;
-  }
-  return `${(bytes / (1024 * 1024)).toFixed(2)} MB`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "mega",
+    separator: " ",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : unit === "kilo" ? 1 : 2),
+  });
 }
diff --git a/extensions/qqbot/src/engine/commands/builtin/register-clear-storage.ts b/extensions/qqbot/src/engine/commands/builtin/register-clear-storage.ts
index 3c545f97b90..195e5e10eef 100644
--- a/extensions/qqbot/src/engine/commands/builtin/register-clear-storage.ts
+++ b/extensions/qqbot/src/engine/commands/builtin/register-clear-storage.ts
@@ -1,6 +1,7 @@
 // Qqbot plugin module implements register clear storage behavior.
 import fs from "node:fs";
 import path from "node:path";
+import { formatByteSize } from "openclaw/plugin-sdk/number-runtime";
 import { getQQBotMediaPath } from "../../utils/platform.js";
 import type { SlashCommandRegistry } from "../slash-commands.js";
 
@@ -36,16 +37,12 @@ function scanDirectoryFiles(dirPath: string): { filePath: string; size: number }
 }
 
 function formatBytes(bytes: number): string {
-  if (bytes < 1024) {
-    return `${bytes} B`;
-  }
-  if (bytes < 1024 * 1024) {
-    return `${(bytes / 1024).toFixed(1)} KB`;
-  }
-  if (bytes < 1024 * 1024 * 1024) {
-    return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
-  }
-  return `${(bytes / (1024 * 1024 * 1024)).toFixed(1)} GB`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "giga",
+    separator: " ",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : 1),
+  });
 }
 
 function removeEmptyDirs(dirPath: string): void {
diff --git a/extensions/qqbot/src/engine/utils/file-utils.test.ts b/extensions/qqbot/src/engine/utils/file-utils.test.ts
index 20b32e355e6..7637d67df59 100644
--- a/extensions/qqbot/src/engine/utils/file-utils.test.ts
+++ b/extensions/qqbot/src/engine/utils/file-utils.test.ts
@@ -31,11 +31,20 @@ import {
   checkFileSize,
   downloadFile,
   fileExistsAsync,
+  formatFileSize,
   getImageMimeType,
   getMimeType,
   readFileAsync,
 } from "./file-utils.js";
 
+describe("formatFileSize", () => {
+  it("preserves compact binary-scaled upload labels", () => {
+    expect(formatFileSize(512)).toBe("512B");
+    expect(formatFileSize(1536)).toBe("1.5KB");
+    expect(formatFileSize(2 * 1024 * 1024)).toBe("2.0MB");
+  });
+});
+
 describe("qqbot file-utils MIME helpers", () => {
   it("uses the shared media MIME table for extension inference", () => {
     expect(getMimeType("voice.mp3")).toBe("audio/mpeg");
diff --git a/extensions/qqbot/src/engine/utils/file-utils.ts b/extensions/qqbot/src/engine/utils/file-utils.ts
index 92664d718fd..eb980526bc2 100644
--- a/extensions/qqbot/src/engine/utils/file-utils.ts
+++ b/extensions/qqbot/src/engine/utils/file-utils.ts
@@ -3,6 +3,7 @@ import crypto from "node:crypto";
 import * as fs from "node:fs";
 import * as path from "node:path";
 import { mimeTypeFromFilePath } from "openclaw/plugin-sdk/media-mime";
+import { formatByteSize } from "openclaw/plugin-sdk/number-runtime";
 import {
   openLocalFileSafely,
   readRegularFile,
@@ -124,13 +125,12 @@ export async function fileExistsAsync(filePath: string): Promise<boolean> {
 
 /** Format a byte count into a human-readable size string. */
 export function formatFileSize(bytes: number): string {
-  if (bytes < 1024) {
-    return `${bytes}B`;
-  }
-  if (bytes < 1024 * 1024) {
-    return `${(bytes / 1024).toFixed(1)}KB`;
-  }
-  return `${(bytes / (1024 * 1024)).toFixed(1)}MB`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "mega",
+    separator: "",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : 1),
+  });
 }
 
 /** Infer a MIME type from the file extension. */
diff --git a/packages/normalization-core/src/format.test.ts b/packages/normalization-core/src/format.test.ts
new file mode 100644
index 00000000000..aa5e578ffdb
--- /dev/null
+++ b/packages/normalization-core/src/format.test.ts
@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import { formatByteSize } from "./format.js";
+
+describe("formatByteSize", () => {
+  it.each([
+    [1024, { style: "iec", maxUnit: "mega", separator: " ", fractionDigits: 1 }, "1.0 KiB"],
+    [1024, { style: "legacy-binary", maxUnit: "mega", separator: "", fractionDigits: 1 }, "1.0KB"],
+    [
+      5 * 1024 * 1024,
+      { style: "legacy-binary", maxUnit: "kilo", separator: " ", fractionDigits: 1 },
+      "5120.0 KB",
+    ],
+  ] as const)("formats %s bytes", (bytes, options, expected) => {
+    expect(formatByteSize(bytes, options)).toBe(expected);
+  });
+
+  it("supports caller-owned dynamic precision and rounding", () => {
+    expect(
+      formatByteSize(Math.floor(99.6 * 1024 * 1024), {
+        style: "legacy-binary",
+        maxUnit: "giga",
+        separator: " ",
+        fractionDigits: (_value, unit) => (unit === "giga" ? 1 : unit === "byte" ? null : 0),
+        floorUnits: ["kilo", "mega"],
+      }),
+    ).toBe("99 MB");
+  });
+});
diff --git a/packages/normalization-core/src/format.ts b/packages/normalization-core/src/format.ts
new file mode 100644
index 00000000000..09121269cbd
--- /dev/null
+++ b/packages/normalization-core/src/format.ts
@@ -0,0 +1,41 @@
+type ByteSizeUnit = "byte" | "kilo" | "mega" | "giga" | "tera";
+type ByteSizeStyle = "iec" | "legacy-binary";
+
+type ByteSizeFormatOptions = {
+  style: ByteSizeStyle;
+  maxUnit: ByteSizeUnit;
+  separator: "" | " ";
+  fractionDigits: number | ((value: number, unit: ByteSizeUnit) => number | null);
+  floorUnits?: readonly ByteSizeUnit[];
+};
+
+const BYTE_SIZE_UNITS: readonly ByteSizeUnit[] = ["byte", "kilo", "mega", "giga", "tera"];
+const BYTE_SIZE_STYLES = {
+  iec: { base: 1024, labels: ["B", "KiB", "MiB", "GiB", "TiB"] },
+  "legacy-binary": { base: 1024, labels: ["B", "KB", "MB", "GB", "TB"] },
+} as const satisfies Record<ByteSizeStyle, { base: number; labels: readonly string[] }>;
+
+/** Formats a byte count with caller-explicit scale, labels, precision, and unit cap. */
+export function formatByteSize(bytes: number, options: ByteSizeFormatOptions): string {
+  const { base, labels } = BYTE_SIZE_STYLES[options.style];
+  const maxUnitIndex = BYTE_SIZE_UNITS.indexOf(options.maxUnit);
+  let unitIndex = 0;
+  let value = bytes;
+  while (value >= base && unitIndex < maxUnitIndex) {
+    value /= base;
+    unitIndex += 1;
+  }
+
+  const unit = BYTE_SIZE_UNITS[unitIndex];
+  const fractionDigits =
+    typeof options.fractionDigits === "function"
+      ? options.fractionDigits(value, unit)
+      : options.fractionDigits;
+  if (fractionDigits === null) {
+    return `${value}${options.separator}${labels[unitIndex]}`;
+  }
+  if (options.floorUnits?.includes(unit)) {
+    value = Math.floor(value * 10 ** fractionDigits) / 10 ** fractionDigits;
+  }
+  return `${value.toFixed(fractionDigits)}${options.separator}${labels[unitIndex]}`;
+}
diff --git a/packages/normalization-core/src/index.ts b/packages/normalization-core/src/index.ts
index 9bc9d57d82e..e0e122eae80 100644
--- a/packages/normalization-core/src/index.ts
+++ b/packages/normalization-core/src/index.ts
@@ -2,6 +2,7 @@
 
 export * from "./boolean-coercion.js";
 export * from "./error-coercion.js";
+export * from "./format.js";
 export * from "./json-coercion.js";
 export * from "./number-coercion.js";
 export * from "./record-coerce.js";
diff --git a/scripts/plugin-sdk-surface-report.mjs b/scripts/plugin-sdk-surface-report.mjs
index 067888b19e0..83dce1f0608 100644
--- a/scripts/plugin-sdk-surface-report.mjs
+++ b/scripts/plugin-sdk-surface-report.mjs
@@ -192,12 +192,12 @@ export function readPluginSdkSurfaceBudgets(env = process.env) {
     ),
     publicExports: readPluginSdkSurfaceBudgetEnv(
       "OPENCLAW_PLUGIN_SDK_MAX_PUBLIC_EXPORTS",
-      10453,
+      10454,
       env,
     ),
     publicFunctionExports: readPluginSdkSurfaceBudgetEnv(
       "OPENCLAW_PLUGIN_SDK_MAX_PUBLIC_FUNCTION_EXPORTS",
-      5218,
+      5219,
       env,
     ),
     publicDeprecatedExports: readPluginSdkSurfaceBudgetEnv(
diff --git a/src/agents/agent-tools.read.ts b/src/agents/agent-tools.read.ts
index 7bc7c688059..b3bf74259ca 100644
--- a/src/agents/agent-tools.read.ts
+++ b/src/agents/agent-tools.read.ts
@@ -1,12 +1,12 @@
-/**
- * Read/write/edit tool wrappers for host and sandbox workspaces.
- * Adds workspace-root guards, adaptive read paging, image validation, memory
- * append-only writes, and parameter cleanup around the session file tools.
- */
+// Read/write/edit tool wrappers for host and sandbox workspaces.
+// Adds workspace-root guards, adaptive read paging, image validation, memory
+// append-only writes, and parameter cleanup around the session file tools.
+
 import fs from "node:fs/promises";
 import path from "node:path";
 import { URL } from "node:url";
 import { detectMime } from "@openclaw/media-core/mime";
+import { formatByteSize } from "@openclaw/normalization-core";
 import { isWindowsDrivePath } from "../infra/archive-path.js";
 import { toErrorObject } from "../infra/errors.js";
 import {
@@ -96,13 +96,12 @@ function malformedXmlArgValuePathError(key: string): Error {
 }
 
 function formatBytes(bytes: number): string {
-  if (bytes >= 1024 * 1024) {
-    return `${(bytes / (1024 * 1024)).toFixed(1)}MB`;
-  }
-  if (bytes >= 1024) {
-    return `${Math.round(bytes / 1024)}KB`;
-  }
-  return `${bytes}B`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "mega",
+    separator: "",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : unit === "kilo" ? 0 : 1),
+  });
 }
 
 function getToolResultText(result: AgentToolResult<unknown>): string | undefined {
diff --git a/src/agents/tool-images.ts b/src/agents/tool-images.ts
index 0550c3a5534..39f392ff7ab 100644
--- a/src/agents/tool-images.ts
+++ b/src/agents/tool-images.ts
@@ -4,7 +4,7 @@
  * Downscales and recompresses oversized base64 image blocks before provider replay.
  */
 import { canonicalizeBase64 } from "@openclaw/media-core/base64";
-import { resolveIntegerOption } from "@openclaw/normalization-core/number-coercion";
+import { formatByteSize, resolveIntegerOption } from "@openclaw/normalization-core";
 import { toErrorObject } from "../infra/errors.js";
 import type { ImageContent } from "../llm/types.js";
 import { createSubsystemLogger } from "../logging/subsystem.js";
@@ -97,10 +97,12 @@ function formatBytesShort(bytes: number): string {
   if (!Number.isFinite(bytes) || bytes < 1024) {
     return `${Math.max(0, Math.round(bytes))}B`;
   }
-  if (bytes < 1024 * 1024) {
-    return `${(bytes / 1024).toFixed(1)}KB`;
-  }
-  return `${(bytes / (1024 * 1024)).toFixed(2)}MB`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "mega",
+    separator: "",
+    fractionDigits: (_value, unit) => (unit === "kilo" ? 1 : 2),
+  });
 }
 
 function fileNameFromPathLike(pathLike: string): string | undefined {
diff --git a/src/cli/gateway-cli/register.ts b/src/cli/gateway-cli/register.ts
index 6e1fc378914..c805f46e6b3 100644
--- a/src/cli/gateway-cli/register.ts
+++ b/src/cli/gateway-cli/register.ts
@@ -1,4 +1,5 @@
 // Commander registration for gateway status, health, diagnostics, discovery, and run commands.
+import { formatByteSize } from "@openclaw/normalization-core";
 import type { Command } from "commander";
 import { formatDocsLink } from "../../../packages/terminal-core/src/links.js";
 import { colorize, isRich, theme } from "../../../packages/terminal-core/src/theme.js";
@@ -232,15 +233,12 @@ function formatBytes(value: number | undefined): string {
   if (value === undefined) {
     return "n/a";
   }
-  const units = ["B", "KiB", "MiB", "GiB"];
-  let amount = value;
-  let unitIndex = 0;
-  while (amount >= 1024 && unitIndex < units.length - 1) {
-    amount /= 1024;
-    unitIndex += 1;
-  }
-  const digits = unitIndex === 0 || amount >= 100 ? 0 : 1;
-  return `${amount.toFixed(digits)} ${units[unitIndex]}`;
+  return formatByteSize(value, {
+    style: "iec",
+    maxUnit: "giga",
+    separator: " ",
+    fractionDigits: (amount, unit) => (unit === "byte" || amount >= 100 ? 0 : 1),
+  });
 }
 
 function formatStabilityEvent(record: DiagnosticStabilityEventRecord): string {
diff --git a/src/commands/doctor-disk-space.ts b/src/commands/doctor-disk-space.ts
index 291e32f7831..10ab2e17a9d 100644
--- a/src/commands/doctor-disk-space.ts
+++ b/src/commands/doctor-disk-space.ts
@@ -1,5 +1,6 @@
-/** Doctor contribution for low disk space around the OpenClaw state directory. */
+// Doctor contribution for low disk space around the OpenClaw state directory.
 import os from "node:os";
+import { formatByteSize } from "@openclaw/normalization-core";
 import { note } from "../../packages/terminal-core/src/note.js";
 import type { OpenClawConfig } from "../config/config.js";
 import { resolveStateDir } from "../config/paths.js";
@@ -28,16 +29,13 @@ export function formatBytes(bytes: number): string {
   if (bytes < 0 || !Number.isFinite(bytes)) {
     return "unknown";
   }
-  if (bytes >= 1024 * 1024 * 1024) {
-    return `${(bytes / (1024 * 1024 * 1024)).toFixed(1)} GB`;
-  }
-  if (bytes >= 1024 * 1024) {
-    return `${Math.floor(bytes / (1024 * 1024))} MB`;
-  }
-  if (bytes >= 1024) {
-    return `${Math.floor(bytes / 1024)} KB`;
-  }
-  return `${bytes} B`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "giga",
+    separator: " ",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : unit === "giga" ? 1 : 0),
+    floorUnits: ["kilo", "mega"],
+  });
 }
 
 /**
diff --git a/src/plugin-sdk/number-runtime.ts b/src/plugin-sdk/number-runtime.ts
index ce559cbc873..6f40bb3cb52 100644
--- a/src/plugin-sdk/number-runtime.ts
+++ b/src/plugin-sdk/number-runtime.ts
@@ -1,5 +1,6 @@
 // Numeric coercion helpers for plugin runtime inputs.
 
+export { formatByteSize } from "../../packages/normalization-core/src/format.js";
 export {
   asDateTimestampMs,
   asFiniteNumberInRange,
diff --git a/ui/src/lib/agents/display.test.ts b/ui/src/lib/agents/display.test.ts
index 0c451d33258..cf330d3f37e 100644
--- a/ui/src/lib/agents/display.test.ts
+++ b/ui/src/lib/agents/display.test.ts
@@ -8,11 +8,22 @@ import {
 import {
   assistantAvatarFallbackUrl,
   buildAgentContext,
+  formatBytes,
   resolveConfiguredCronModelSuggestions,
   resolveEffectiveModelFallbacks,
   sortLocaleStrings,
 } from "./display.ts";
 
+describe("formatBytes", () => {
+  it("preserves the Control UI byte-size display contract", () => {
+    expect(formatBytes(undefined)).toBe("-");
+    expect(formatBytes(512)).toBe("512 B");
+    expect(formatBytes(1536)).toBe("1.5 KB");
+    expect(formatBytes(12 * 1024)).toBe("12 KB");
+    expect(formatBytes(2 * 1024 * 1024)).toBe("2.0 MB");
+  });
+});
+
 describe("resolveEffectiveModelFallbacks", () => {
   it("inherits defaults when no entry fallbacks are configured", () => {
     const entryModel = undefined;
diff --git a/ui/src/lib/agents/display.ts b/ui/src/lib/agents/display.ts
index 506c0f87612..408313cc14f 100644
--- a/ui/src/lib/agents/display.ts
+++ b/ui/src/lib/agents/display.ts
@@ -1,4 +1,5 @@
 // Control UI view renders agents utils screen content.
+import { formatByteSize } from "@openclaw/normalization-core";
 import { html, nothing } from "lit";
 import {
   expandToolGroups,
@@ -236,17 +237,12 @@ export function formatBytes(bytes?: number) {
   if (bytes == null || !Number.isFinite(bytes)) {
     return "-";
   }
-  if (bytes < 1024) {
-    return `${bytes} B`;
-  }
-  const units = ["KB", "MB", "GB", "TB"];
-  let size = bytes / 1024;
-  let unitIndex = 0;
-  while (size >= 1024 && unitIndex < units.length - 1) {
-    size /= 1024;
-    unitIndex += 1;
-  }
-  return `${size.toFixed(size < 10 ? 1 : 0)} ${units[unitIndex]}`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "tera",
+    separator: " ",
+    fractionDigits: (value, unit) => (unit === "byte" ? null : value < 10 ? 1 : 0),
+  });
 }
 
 export function resolveAgentConfig(config: Record<string, unknown> | null, agentId: string) {
diff --git a/ui/src/pages/skill-workshop/proposals.ts b/ui/src/pages/skill-workshop/proposals.ts
index fa443afc085..3db2c481d8b 100644
--- a/ui/src/pages/skill-workshop/proposals.ts
+++ b/ui/src/pages/skill-workshop/proposals.ts
@@ -1,5 +1,6 @@
-import type { AgentSelectionCapability } from "../../app/agent-selection.ts";
 // Control UI controller manages skill workshop gateway state.
+import { formatByteSize } from "@openclaw/normalization-core";
+import type { AgentSelectionCapability } from "../../app/agent-selection.ts";
 import type { ApplicationGateway } from "../../app/context.ts";
 import {
   normalizeAgentId,
@@ -251,10 +252,12 @@ function formatBytes(bytes: number): string {
   if (!Number.isFinite(bytes) || bytes <= 0) {
     return "0 B";
   }
-  if (bytes < 1024) {
-    return `${bytes} B`;
-  }
-  return `${(bytes / 1024).toFixed(1)} KB`;
+  return formatByteSize(bytes, {
+    style: "legacy-binary",
+    maxUnit: "kilo",
+    separator: " ",
+    fractionDigits: (_value, unit) => (unit === "byte" ? null : 1),
+  });
 }
 
 function byteLength(value: string): number {