diff --git a/dsh-plugin-desktop/src/log-level.ts b/dsh-plugin-desktop/src/log-level.ts
new file mode 100644
index 0000000000..d3a99dbd8d
--- /dev/null
+++ b/dsh-plugin-desktop/src/log-level.ts
@@ -0,0 +1,17 @@
+/** One Cordis logger severity, mirroring `@deepseek-ai/cordis`'s `LoggerType`. */
+export type LogType = 'error' | 'info' | 'warn' | 'debug'
+
+/** User-selectable log verbosity threshold. */
+export type LogLevel = 'debug' | 'info' | 'warn' | 'error'
+
+const VERBOSITY: Record<LogType, number> = { error: 0, warn: 1, info: 2, debug: 3 }
+
+/** Whether a message of `type` should be emitted at `threshold`. */
+export function shouldEmit(type: LogType, threshold: LogLevel): boolean {
+  return VERBOSITY[type] <= VERBOSITY[threshold]
+}
+
+/** Whether a message of `type` belongs in the per-day error log. */
+export function isErrorType(type: LogType): boolean {
+  return type === 'warn' || type === 'error'
+}
diff --git a/dsh-plugin-desktop/tests/log-level.spec.ts b/dsh-plugin-desktop/tests/log-level.spec.ts
new file mode 100644
index 0000000000..5b8d4b34d3
--- /dev/null
+++ b/dsh-plugin-desktop/tests/log-level.spec.ts
@@ -0,0 +1,34 @@
+import { describe, expect, it } from 'vitest'
+import { isErrorType, shouldEmit } from '../src/log-level.ts'
+
+describe('shouldEmit', () => {
+  it('emits nothing above the threshold', () => {
+    expect(shouldEmit('debug', 'info')).toBe(false)
+    expect(shouldEmit('info', 'info')).toBe(true)
+    expect(shouldEmit('warn', 'info')).toBe(true)
+    expect(shouldEmit('error', 'info')).toBe(true)
+  })
+
+  it('emits only errors at the error threshold', () => {
+    expect(shouldEmit('error', 'error')).toBe(true)
+    expect(shouldEmit('warn', 'error')).toBe(false)
+    expect(shouldEmit('info', 'error')).toBe(false)
+    expect(shouldEmit('debug', 'error')).toBe(false)
+  })
+
+  it('emits everything at the debug threshold', () => {
+    expect(shouldEmit('debug', 'debug')).toBe(true)
+    expect(shouldEmit('info', 'debug')).toBe(true)
+    expect(shouldEmit('warn', 'debug')).toBe(true)
+    expect(shouldEmit('error', 'debug')).toBe(true)
+  })
+})
+
+describe('isErrorType', () => {
+  it('treats warn and error as the error log', () => {
+    expect(isErrorType('warn')).toBe(true)
+    expect(isErrorType('error')).toBe(true)
+    expect(isErrorType('info')).toBe(false)
+    expect(isErrorType('debug')).toBe(false)
+  })
+})