diff --git a/packages/omo-claude/plugin/components/telemetry/src/atomic-write.ts b/packages/omo-claude/plugin/components/telemetry/src/atomic-write.ts
new file mode 100644
index 000000000..c87df29d4
--- /dev/null
+++ b/packages/omo-claude/plugin/components/telemetry/src/atomic-write.ts
@@ -0,0 +1,22 @@
+import { renameSync, unlinkSync, writeFileSync } from "node:fs"
+
+export function writeFileAtomically(filePath: string, content: string): void {
+  const tempPath = `${filePath}.tmp`
+  writeFileSync(tempPath, content, "utf-8")
+
+  try {
+    renameSync(tempPath, filePath)
+  } catch (error) {
+    const isPermissionError =
+      error instanceof Error &&
+      (error.message.includes("EPERM") || error.message.includes("EACCES"))
+
+    if (process.platform === "win32" && isPermissionError) {
+      unlinkSync(filePath)
+      renameSync(tempPath, filePath)
+      return
+    }
+
+    throw error
+  }
+}
diff --git a/packages/omo-claude/plugin/components/telemetry/src/data-path.ts b/packages/omo-claude/plugin/components/telemetry/src/data-path.ts
new file mode 100644
index 000000000..c232fecc8
--- /dev/null
+++ b/packages/omo-claude/plugin/components/telemetry/src/data-path.ts
@@ -0,0 +1,45 @@
+import { accessSync, constants, mkdirSync } from "node:fs"
+import os from "node:os"
+import path from "node:path"
+
+import { CACHE_DIR_NAME } from "./product-identity.js"
+
+type OsProvider = Pick<typeof os, "homedir" | "tmpdir">
+
+let osProviderOverride: OsProvider | null = null
+
+export function getOsProvider(): OsProvider {
+  return osProviderOverride ?? os
+}
+
+/** @internal test-only */
+export function __setOsProviderForTesting(provider: OsProvider): void {
+  osProviderOverride = provider
+}
+
+/** @internal test-only */
+export function __resetOsProviderForTesting(): void {
+  osProviderOverride = null
+}
+
+function resolveWritableDirectory(preferredDir: string, fallbackSuffix: string): string {
+  try {
+    mkdirSync(preferredDir, { recursive: true })
+    accessSync(preferredDir, constants.W_OK)
+    return preferredDir
+  } catch {
+    const fallbackDir = path.join(getOsProvider().tmpdir(), fallbackSuffix)
+    mkdirSync(fallbackDir, { recursive: true })
+    return fallbackDir
+  }
+}
+
+export function getDataDir(): string {
+  const preferredDataDir =
+    process.env["XDG_DATA_HOME"] ?? path.join(getOsProvider().homedir(), ".local", "share")
+  return resolveWritableDirectory(preferredDataDir, `${CACHE_DIR_NAME}-data`)
+}
+
+export function getActivityStateDir(): string {
+  return path.join(getDataDir(), CACHE_DIR_NAME)
+}
diff --git a/packages/omo-claude/plugin/components/telemetry/src/env-flags.ts b/packages/omo-claude/plugin/components/telemetry/src/env-flags.ts
new file mode 100644
index 000000000..c1b6364b9
--- /dev/null
+++ b/packages/omo-claude/plugin/components/telemetry/src/env-flags.ts
@@ -0,0 +1,43 @@
+import {
+  DEFAULT_POSTHOG_API_KEY,
+  DEFAULT_POSTHOG_HOST,
+} from "./product-identity.js"
+
+function normalizeEnvValue(value: string | undefined): string | undefined {
+  return value?.trim().toLowerCase()
+}
+
+function isDisableFlag(value: string | undefined): boolean {
+  const normalized = normalizeEnvValue(value)
+  return normalized === "1" || normalized === "true"
+}
+
+function isTelemetryOptOutFlag(value: string | undefined): boolean {
+  const normalized = normalizeEnvValue(value)
+  return normalized === "0" || normalized === "false" || normalized === "no"
+}
+
+export function shouldDisablePostHog(): boolean {
+  return (
+    isDisableFlag(process.env["OMO_DISABLE_POSTHOG"]) ||
+    isTelemetryOptOutFlag(process.env["OMO_SEND_ANONYMOUS_TELEMETRY"]) ||
+    isDisableFlag(process.env["OMO_CLAUDE_DISABLE_POSTHOG"]) ||
+    isTelemetryOptOutFlag(process.env["OMO_CLAUDE_SEND_ANONYMOUS_TELEMETRY"])
+  )
+}
+
+export function getPostHogApiKey(): string {
+  const explicit = process.env["POSTHOG_API_KEY"]
+  if (explicit === undefined) {
+    return DEFAULT_POSTHOG_API_KEY
+  }
+  return explicit.trim()
+}
+
+export function hasPostHogApiKey(): boolean {
+  return getPostHogApiKey().length > 0
+}
+
+export function getPostHogHost(): string {
+  return process.env["POSTHOG_HOST"]?.trim() || DEFAULT_POSTHOG_HOST
+}
diff --git a/packages/omo-claude/plugin/components/telemetry/src/posthog-activity-state.ts b/packages/omo-claude/plugin/components/telemetry/src/posthog-activity-state.ts
new file mode 100644
index 000000000..b9fa9a8b6
--- /dev/null
+++ b/packages/omo-claude/plugin/components/telemetry/src/posthog-activity-state.ts
@@ -0,0 +1,81 @@
+import { existsSync, mkdirSync, readFileSync } from "node:fs"
+import { join } from "node:path"
+
+import { writeFileAtomically } from "./atomic-write.js"
+import { getActivityStateDir } from "./data-path.js"
+
+export type PostHogActivityState = {
+  readonly lastActiveDayUTC?: string
+}
+
+export type PostHogActivityCaptureState = {
+  readonly dayUTC: string
+  readonly captureDaily: boolean
+}
+
+const POSTHOG_ACTIVITY_STATE_FILE = "posthog-activity.json"
+
+function getPostHogActivityStateFilePath(): string {
+  return join(getActivityStateDir(), POSTHOG_ACTIVITY_STATE_FILE)
+}
+
+function getUtcDayString(date: Date): string {
+  return date.toISOString().slice(0, 10)
+}
+
+function isPostHogActivityState(value: unknown): value is PostHogActivityState {
+  return value !== null && typeof value === "object" && !Array.isArray(value)
+}
+
+function readPostHogActivityState(): PostHogActivityState {
+  const stateFilePath = getPostHogActivityStateFilePath()
+
+  if (!existsSync(stateFilePath)) {
+    return {}
+  }
+
+  try {
+    const stateContent = readFileSync(stateFilePath, "utf-8")
+    const stateJson: unknown = JSON.parse(stateContent)
+
+    if (!isPostHogActivityState(stateJson)) {
+      return {}
+    }
+
+    return stateJson
+  } catch {
+    return {}
+  }
+}
+
+function writePostHogActivityState(nextState: PostHogActivityState): void {
+  const stateDir = getActivityStateDir()
+  const stateFilePath = getPostHogActivityStateFilePath()
+
+  try {
+    mkdirSync(stateDir, { recursive: true })
+    writeFileAtomically(stateFilePath, `${JSON.stringify(nextState, null, 2)}\n`)
+  } catch {
+    return
+  }
+}
+
+export function getPostHogActivityCaptureState(
+  now: Date = new Date(),
+): PostHogActivityCaptureState {
+  const state = readPostHogActivityState()
+  const dayUTC = getUtcDayString(now)
+  const captureDaily = state.lastActiveDayUTC !== dayUTC
+
+  if (captureDaily) {
+    writePostHogActivityState({
+      ...state,
+      lastActiveDayUTC: dayUTC,
+    })
+  }
+
+  return {
+    dayUTC,
+    captureDaily,
+  }
+}
diff --git a/packages/omo-claude/plugin/components/telemetry/src/product-identity.ts b/packages/omo-claude/plugin/components/telemetry/src/product-identity.ts
new file mode 100644
index 000000000..ad1b509e7
--- /dev/null
+++ b/packages/omo-claude/plugin/components/telemetry/src/product-identity.ts
@@ -0,0 +1,35 @@
+import { readFileSync } from "node:fs";
+
+export const PRODUCT_NAME = "omo-claude";
+export const PACKAGE_NAME = "@oh-my-opencode/omo-claude";
+export const CACHE_DIR_NAME = "omo-claude";
+export const EVENT_NAME = "omo_claude_daily_active";
+export const LEGACY_PARENT_PACKAGE = "oh-my-opencode";
+export const DEFAULT_POSTHOG_HOST = "https://us.i.posthog.com";
+export const DEFAULT_POSTHOG_API_KEY = "phc_CFJhj5HyvA62QPhvyaUCtaq23aUfznnijg5VaaGkNk74";
+
+type ComponentPackageManifest = { readonly version?: string };
+
+function isComponentPackageManifest(value: unknown): value is ComponentPackageManifest {
+	return value !== null && typeof value === "object" && !Array.isArray(value);
+}
+
+function readComponentVersionFromManifest(): string {
+	try {
+		const manifestUrl = new URL("../package.json", import.meta.url);
+		const manifestText = readFileSync(manifestUrl, "utf-8");
+		const parsed: unknown = JSON.parse(manifestText);
+		if (isComponentPackageManifest(parsed) && typeof parsed.version === "string") {
+			return parsed.version;
+		}
+	} catch {
+		return "0.0.0";
+	}
+	return "0.0.0";
+}
+
+const COMPONENT_VERSION_CACHE = readComponentVersionFromManifest();
+
+export function getComponentVersion(): string {
+	return COMPONENT_VERSION_CACHE;
+}
diff --git a/packages/omo-claude/src/telemetry/atomic-write.ts b/packages/omo-claude/src/telemetry/atomic-write.ts
new file mode 100644
index 000000000..c87df29d4
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/atomic-write.ts
@@ -0,0 +1,22 @@
+import { renameSync, unlinkSync, writeFileSync } from "node:fs"
+
+export function writeFileAtomically(filePath: string, content: string): void {
+  const tempPath = `${filePath}.tmp`
+  writeFileSync(tempPath, content, "utf-8")
+
+  try {
+    renameSync(tempPath, filePath)
+  } catch (error) {
+    const isPermissionError =
+      error instanceof Error &&
+      (error.message.includes("EPERM") || error.message.includes("EACCES"))
+
+    if (process.platform === "win32" && isPermissionError) {
+      unlinkSync(filePath)
+      renameSync(tempPath, filePath)
+      return
+    }
+
+    throw error
+  }
+}
diff --git a/packages/omo-claude/src/telemetry/cross-package-equivalence.test.ts b/packages/omo-claude/src/telemetry/cross-package-equivalence.test.ts
new file mode 100644
index 000000000..41bf1e6c1
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/cross-package-equivalence.test.ts
@@ -0,0 +1,125 @@
+import { describe, expect, it } from "bun:test"
+
+import * as cliIdentity from "./product-identity"
+
+describe("cross-package telemetry identity equivalence", () => {
+  describe("#given the omo-claude CLI telemetry product-identity module and the Claude Code plugin component product-identity module", () => {
+    it("#when both are imported #then PRODUCT_NAME, PACKAGE_NAME, CACHE_DIR_NAME, EVENT_NAME, DEFAULT_POSTHOG_HOST, and DEFAULT_POSTHOG_API_KEY are identical", async () => {
+      const pluginIdentity = await import(
+        "../../plugin/components/telemetry/src/product-identity"
+      )
+
+      expect(pluginIdentity.PRODUCT_NAME).toBe(cliIdentity.PRODUCT_NAME)
+      expect(pluginIdentity.PACKAGE_NAME).toBe(cliIdentity.PACKAGE_NAME)
+      expect(pluginIdentity.CACHE_DIR_NAME).toBe(cliIdentity.CACHE_DIR_NAME)
+      expect(pluginIdentity.EVENT_NAME).toBe(cliIdentity.EVENT_NAME)
+      expect(pluginIdentity.DEFAULT_POSTHOG_HOST).toBe(cliIdentity.DEFAULT_POSTHOG_HOST)
+      expect(pluginIdentity.DEFAULT_POSTHOG_API_KEY).toBe(cliIdentity.DEFAULT_POSTHOG_API_KEY)
+      expect(pluginIdentity.LEGACY_PARENT_PACKAGE).toBe(cliIdentity.LEGACY_PARENT_PACKAGE)
+    })
+  })
+
+  describe("#given the omo-claude CLI env-flags module and the Claude Code plugin component env-flags module", () => {
+    it("#when shouldDisablePostHog is checked under each opt-out env var #then both modules disable on the same flags", async () => {
+      const cliEnv = await import("./env-flags")
+      const pluginEnv = await import(
+        "../../plugin/components/telemetry/src/env-flags"
+      )
+
+      const flags = [
+        "OMO_DISABLE_POSTHOG",
+        "OMO_SEND_ANONYMOUS_TELEMETRY",
+        "OMO_CLAUDE_DISABLE_POSTHOG",
+        "OMO_CLAUDE_SEND_ANONYMOUS_TELEMETRY",
+      ] as const
+      const previousValues = new Map<string, string | undefined>()
+      for (const flag of flags) {
+        previousValues.set(flag, process.env[flag])
+        delete process.env[flag]
+      }
+      try {
+        expect(cliEnv.shouldDisablePostHog()).toBe(false)
+        expect(pluginEnv.shouldDisablePostHog()).toBe(false)
+
+        for (const optOutFlag of ["OMO_DISABLE_POSTHOG", "OMO_CLAUDE_DISABLE_POSTHOG"] as const) {
+          process.env[optOutFlag] = "1"
+          expect(cliEnv.shouldDisablePostHog()).toBe(true)
+          expect(pluginEnv.shouldDisablePostHog()).toBe(true)
+          delete process.env[optOutFlag]
+        }
+
+        for (const sendFlag of ["OMO_SEND_ANONYMOUS_TELEMETRY", "OMO_CLAUDE_SEND_ANONYMOUS_TELEMETRY"] as const) {
+          process.env[sendFlag] = "0"
+          expect(cliEnv.shouldDisablePostHog()).toBe(true)
+          expect(pluginEnv.shouldDisablePostHog()).toBe(true)
+          delete process.env[sendFlag]
+        }
+      } finally {
+        for (const flag of flags) {
+          const previous = previousValues.get(flag)
+          if (previous === undefined) {
+            delete process.env[flag]
+          } else {
+            process.env[flag] = previous
+          }
+        }
+      }
+    })
+  })
+})
+
+describe("cross-product telemetry identity distinctness", () => {
+  describe("#given the omo-claude product-identity module and the omo-codex product-identity module", () => {
+    it("#when both are imported #then EVENT_NAME differs but the shared PostHog project key, host, and LEGACY_PARENT_PACKAGE are equal", async () => {
+      const codexIdentity = await import(
+        "../../../omo-codex/src/telemetry/product-identity.ts"
+      )
+
+      // Distinct branding — must NOT collide across products.
+      expect(cliIdentity.EVENT_NAME).not.toBe(codexIdentity.EVENT_NAME)
+      expect(cliIdentity.EVENT_NAME).toBe("omo_claude_daily_active")
+      expect(codexIdentity.EVENT_NAME).toBe("omo_codex_daily_active")
+      expect(cliIdentity.PRODUCT_NAME).not.toBe(codexIdentity.PRODUCT_NAME)
+      expect(cliIdentity.PACKAGE_NAME).not.toBe(codexIdentity.PACKAGE_NAME)
+      expect(cliIdentity.CACHE_DIR_NAME).not.toBe(codexIdentity.CACHE_DIR_NAME)
+
+      // Shared PostHog project — must be byte-identical across products.
+      expect(cliIdentity.DEFAULT_POSTHOG_API_KEY).toBe(codexIdentity.DEFAULT_POSTHOG_API_KEY)
+      expect(cliIdentity.DEFAULT_POSTHOG_HOST).toBe(codexIdentity.DEFAULT_POSTHOG_HOST)
+      expect(cliIdentity.LEGACY_PARENT_PACKAGE).toBe(codexIdentity.LEGACY_PARENT_PACKAGE)
+    })
+  })
+
+  describe("#given the omo-claude posthog module and the omo-codex posthog module", () => {
+    it("#when getPostHogDistinctId is computed on each #then the distinct-id seeds differ", async () => {
+      const fixedHostname = "distinctness-test-host"
+      const osOverride = {
+        arch: () => "arm64" as const,
+        cpus: () => [],
+        hostname: () => fixedHostname,
+        platform: () => "darwin" as const,
+        release: () => "0.0.0",
+        totalmem: () => 0,
+        type: () => "Darwin",
+      }
+
+      const claudePosthog = await import("./posthog")
+      const codexPosthog = await import(
+        "../../../omo-codex/src/telemetry/posthog.ts"
+      )
+
+      claudePosthog.__setOsProviderForTesting(osOverride)
+      codexPosthog.__setOsProviderForTesting(osOverride)
+      try {
+        const claudeId = claudePosthog.getPostHogDistinctId()
+        const codexId = codexPosthog.getPostHogDistinctId()
+
+        // Same hostname, different salt → different distinct id.
+        expect(claudeId).not.toBe(codexId)
+      } finally {
+        claudePosthog.__resetOsProviderForTesting()
+        codexPosthog.__resetOsProviderForTesting()
+      }
+    })
+  })
+})
diff --git a/packages/omo-claude/src/telemetry/data-path.ts b/packages/omo-claude/src/telemetry/data-path.ts
new file mode 100644
index 000000000..130215215
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/data-path.ts
@@ -0,0 +1,45 @@
+import { accessSync, constants, mkdirSync } from "node:fs"
+import os from "node:os"
+import path from "node:path"
+
+import { CACHE_DIR_NAME } from "./product-identity"
+
+type OsProvider = Pick<typeof os, "homedir" | "tmpdir">
+
+let osProviderOverride: OsProvider | null = null
+
+export function getOsProvider(): OsProvider {
+  return osProviderOverride ?? os
+}
+
+/** @internal test-only */
+export function __setOsProviderForTesting(provider: OsProvider): void {
+  osProviderOverride = provider
+}
+
+/** @internal test-only */
+export function __resetOsProviderForTesting(): void {
+  osProviderOverride = null
+}
+
+function resolveWritableDirectory(preferredDir: string, fallbackSuffix: string): string {
+  try {
+    mkdirSync(preferredDir, { recursive: true })
+    accessSync(preferredDir, constants.W_OK)
+    return preferredDir
+  } catch {
+    const fallbackDir = path.join(getOsProvider().tmpdir(), fallbackSuffix)
+    mkdirSync(fallbackDir, { recursive: true })
+    return fallbackDir
+  }
+}
+
+export function getDataDir(): string {
+  const preferredDataDir =
+    process.env.XDG_DATA_HOME ?? path.join(getOsProvider().homedir(), ".local", "share")
+  return resolveWritableDirectory(preferredDataDir, `${CACHE_DIR_NAME}-data`)
+}
+
+export function getActivityStateDir(): string {
+  return path.join(getDataDir(), CACHE_DIR_NAME)
+}
diff --git a/packages/omo-claude/src/telemetry/env-flags.ts b/packages/omo-claude/src/telemetry/env-flags.ts
new file mode 100644
index 000000000..4f70b383b
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/env-flags.ts
@@ -0,0 +1,43 @@
+import {
+  DEFAULT_POSTHOG_API_KEY,
+  DEFAULT_POSTHOG_HOST,
+} from "./product-identity"
+
+function normalizeEnvValue(value: string | undefined): string | undefined {
+  return value?.trim().toLowerCase()
+}
+
+function isDisableFlag(value: string | undefined): boolean {
+  const normalized = normalizeEnvValue(value)
+  return normalized === "1" || normalized === "true"
+}
+
+function isTelemetryOptOutFlag(value: string | undefined): boolean {
+  const normalized = normalizeEnvValue(value)
+  return normalized === "0" || normalized === "false" || normalized === "no"
+}
+
+export function shouldDisablePostHog(): boolean {
+  return (
+    isDisableFlag(process.env.OMO_DISABLE_POSTHOG) ||
+    isTelemetryOptOutFlag(process.env.OMO_SEND_ANONYMOUS_TELEMETRY) ||
+    isDisableFlag(process.env.OMO_CLAUDE_DISABLE_POSTHOG) ||
+    isTelemetryOptOutFlag(process.env.OMO_CLAUDE_SEND_ANONYMOUS_TELEMETRY)
+  )
+}
+
+export function getPostHogApiKey(): string {
+  const explicit = process.env.POSTHOG_API_KEY
+  if (explicit === undefined) {
+    return DEFAULT_POSTHOG_API_KEY
+  }
+  return explicit.trim()
+}
+
+export function hasPostHogApiKey(): boolean {
+  return getPostHogApiKey().length > 0
+}
+
+export function getPostHogHost(): string {
+  return process.env.POSTHOG_HOST?.trim() || DEFAULT_POSTHOG_HOST
+}
diff --git a/packages/omo-claude/src/telemetry/index.ts b/packages/omo-claude/src/telemetry/index.ts
index 95d84dc98..498df547b 100644
--- a/packages/omo-claude/src/telemetry/index.ts
+++ b/packages/omo-claude/src/telemetry/index.ts
@@ -1,4 +1,12 @@
-// Placeholder — telemetry identity, posthog client, env-flags, and data-path
-// are authored in the telemetry-fork task. Re-exported from here so
-// `@oh-my-opencode/omo-claude/telemetry` resolves throughout the build.
-export {};
+export {
+  __resetActivityStateProviderForTesting,
+  __resetOsProviderForTesting,
+  __setActivityStateProviderForTesting,
+  __setOsProviderForTesting,
+  createCliPostHog,
+  createInstallPostHog,
+  createPluginPostHog,
+  getPostHogDistinctId,
+} from "./posthog"
+
+export type { PostHogActivityReason, PostHogClient } from "./posthog"
diff --git a/packages/omo-claude/src/telemetry/posthog-activity-state.ts b/packages/omo-claude/src/telemetry/posthog-activity-state.ts
new file mode 100644
index 000000000..9cccf2475
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/posthog-activity-state.ts
@@ -0,0 +1,81 @@
+import { existsSync, mkdirSync, readFileSync } from "node:fs"
+import { join } from "node:path"
+
+import { writeFileAtomically } from "./atomic-write"
+import { getActivityStateDir } from "./data-path"
+
+export type PostHogActivityState = {
+  readonly lastActiveDayUTC?: string
+}
+
+export type PostHogActivityCaptureState = {
+  readonly dayUTC: string
+  readonly captureDaily: boolean
+}
+
+const POSTHOG_ACTIVITY_STATE_FILE = "posthog-activity.json"
+
+function getPostHogActivityStateFilePath(): string {
+  return join(getActivityStateDir(), POSTHOG_ACTIVITY_STATE_FILE)
+}
+
+function getUtcDayString(date: Date): string {
+  return date.toISOString().slice(0, 10)
+}
+
+function isPostHogActivityState(value: unknown): value is PostHogActivityState {
+  return value !== null && typeof value === "object" && !Array.isArray(value)
+}
+
+function readPostHogActivityState(): PostHogActivityState {
+  const stateFilePath = getPostHogActivityStateFilePath()
+
+  if (!existsSync(stateFilePath)) {
+    return {}
+  }
+
+  try {
+    const stateContent = readFileSync(stateFilePath, "utf-8")
+    const stateJson: unknown = JSON.parse(stateContent)
+
+    if (!isPostHogActivityState(stateJson)) {
+      return {}
+    }
+
+    return stateJson
+  } catch {
+    return {}
+  }
+}
+
+function writePostHogActivityState(nextState: PostHogActivityState): void {
+  const stateDir = getActivityStateDir()
+  const stateFilePath = getPostHogActivityStateFilePath()
+
+  try {
+    mkdirSync(stateDir, { recursive: true })
+    writeFileAtomically(stateFilePath, `${JSON.stringify(nextState, null, 2)}\n`)
+  } catch {
+    return
+  }
+}
+
+export function getPostHogActivityCaptureState(
+  now: Date = new Date(),
+): PostHogActivityCaptureState {
+  const state = readPostHogActivityState()
+  const dayUTC = getUtcDayString(now)
+  const captureDaily = state.lastActiveDayUTC !== dayUTC
+
+  if (captureDaily) {
+    writePostHogActivityState({
+      ...state,
+      lastActiveDayUTC: dayUTC,
+    })
+  }
+
+  return {
+    dayUTC,
+    captureDaily,
+  }
+}
diff --git a/packages/omo-claude/src/telemetry/posthog.ts b/packages/omo-claude/src/telemetry/posthog.ts
new file mode 100644
index 000000000..2c20953b5
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/posthog.ts
@@ -0,0 +1,188 @@
+import { createHash } from "node:crypto"
+import os from "node:os"
+
+import { PostHog } from "posthog-node"
+import packageJson from "../../package.json" with { type: "json" }
+
+import { getPostHogApiKey, getPostHogHost, hasPostHogApiKey, shouldDisablePostHog } from "./env-flags"
+import { getPostHogActivityCaptureState } from "./posthog-activity-state"
+import {
+  DEFAULT_POSTHOG_API_KEY,
+  DEFAULT_POSTHOG_HOST,
+  EVENT_NAME,
+  PACKAGE_NAME,
+  PRODUCT_NAME,
+} from "./product-identity"
+
+export { DEFAULT_POSTHOG_API_KEY, DEFAULT_POSTHOG_HOST }
+
+export type PostHogSource = "cli" | "plugin" | "install"
+export type PostHogActivityReason = "install_started" | "install_completed" | "cli_run" | "session_start"
+
+export type PostHogClient = {
+  trackActive: (distinctId: string, reason: PostHogActivityReason) => void
+  shutdown: () => Promise<void>
+}
+
+type OsProvider = Pick<typeof os, "arch" | "cpus" | "hostname" | "platform" | "release" | "totalmem" | "type">
+type ActivityStateProvider = typeof getPostHogActivityCaptureState
+
+let osProviderOverride: OsProvider | null = null
+let activityStateProviderOverride: ActivityStateProvider | null = null
+
+const NO_OP_POSTHOG: PostHogClient = {
+  trackActive: () => undefined,
+  shutdown: async () => undefined,
+}
+
+type PostHogCaptureEvent = Parameters<PostHog["capture"]>[0]
+
+function resolveOsProvider(): OsProvider {
+  return osProviderOverride ?? os
+}
+
+function resolveActivityStateProvider(): ActivityStateProvider {
+  return activityStateProviderOverride ?? getPostHogActivityCaptureState
+}
+
+function getSafeCpuInfo(): { readonly count: number; readonly model: string | undefined } {
+  try {
+    const cpuInfo = resolveOsProvider().cpus()
+    return {
+      count: cpuInfo.length,
+      model: cpuInfo[0]?.model,
+    }
+  } catch {
+    return {
+      count: 0,
+      model: undefined,
+    }
+  }
+}
+
+function getSharedProperties(source: PostHogSource): NonNullable<PostHogCaptureEvent["properties"]> {
+  const osProvider = resolveOsProvider()
+  const cpuInfo = getSafeCpuInfo()
+
+  return {
+    platform: PRODUCT_NAME,
+    product_name: PRODUCT_NAME,
+    package_name: PACKAGE_NAME,
+    package_version: packageJson.version,
+    runtime: "bun",
+    runtime_version: process.versions.bun ?? process.version,
+    source,
+    $os: osProvider.platform(),
+    $os_version: osProvider.release(),
+    os_arch: osProvider.arch(),
+    os_type: osProvider.type(),
+    cpu_count: cpuInfo.count,
+    cpu_model: cpuInfo.model,
+    total_memory_gb: Math.round(osProvider.totalmem() / 1024 / 1024 / 1024),
+    locale: Intl.DateTimeFormat().resolvedOptions().locale,
+    timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
+    shell: process.env.SHELL,
+    ci: Boolean(process.env.CI),
+    terminal: process.env.TERM_PROGRAM,
+  }
+}
+
+function createPostHogClient(
+  source: PostHogSource,
+  options: ConstructorParameters<typeof PostHog>[1],
+): PostHogClient {
+  if (shouldDisablePostHog() || !hasPostHogApiKey()) {
+    return NO_OP_POSTHOG
+  }
+
+  let client: PostHog
+  try {
+    client = new PostHog(getPostHogApiKey(), {
+      ...options,
+      host: getPostHogHost(),
+      disableGeoip: false,
+    })
+  } catch {
+    return NO_OP_POSTHOG
+  }
+
+  const sharedProperties = getSharedProperties(source)
+
+  return {
+    trackActive: (distinctId, reason) => {
+      const activityState = resolveActivityStateProvider()()
+      if (!activityState.captureDaily) {
+        return
+      }
+
+      client.capture({
+        distinctId,
+        event: EVENT_NAME,
+        properties: {
+          ...sharedProperties,
+          $process_person_profile: false,
+          day_utc: activityState.dayUTC,
+          reason,
+        },
+      })
+    },
+    shutdown: async () => client.shutdown(),
+  }
+}
+
+export function getPostHogDistinctId(): string {
+  return createHash("sha256").update(`omo-claude:${resolveOsProvider().hostname()}`).digest("hex")
+}
+
+export function createCliPostHog(): PostHogClient {
+  return createPostHogClient("cli", {
+    enableExceptionAutocapture: false,
+    enableLocalEvaluation: false,
+    strictLocalEvaluation: true,
+    disableRemoteConfig: true,
+    flushAt: 1,
+    flushInterval: 0,
+  })
+}
+
+export function createInstallPostHog(): PostHogClient {
+  return createPostHogClient("install", {
+    enableExceptionAutocapture: false,
+    enableLocalEvaluation: false,
+    strictLocalEvaluation: true,
+    disableRemoteConfig: true,
+    flushAt: 1,
+    flushInterval: 0,
+  })
+}
+
+export function createPluginPostHog(): PostHogClient {
+  return createPostHogClient("plugin", {
+    enableExceptionAutocapture: false,
+    enableLocalEvaluation: false,
+    strictLocalEvaluation: true,
+    disableRemoteConfig: true,
+    flushAt: 1,
+    flushInterval: 0,
+  })
+}
+
+/** @internal test-only */
+export function __setOsProviderForTesting(provider: OsProvider): void {
+  osProviderOverride = provider
+}
+
+/** @internal test-only */
+export function __resetOsProviderForTesting(): void {
+  osProviderOverride = null
+}
+
+/** @internal test-only */
+export function __setActivityStateProviderForTesting(provider: ActivityStateProvider): void {
+  activityStateProviderOverride = provider
+}
+
+/** @internal test-only */
+export function __resetActivityStateProviderForTesting(): void {
+  activityStateProviderOverride = null
+}
diff --git a/packages/omo-claude/src/telemetry/product-identity.ts b/packages/omo-claude/src/telemetry/product-identity.ts
new file mode 100644
index 000000000..2d3949c73
--- /dev/null
+++ b/packages/omo-claude/src/telemetry/product-identity.ts
@@ -0,0 +1,13 @@
+import packageJson from "../../package.json" with { type: "json" }
+
+export const PRODUCT_NAME = "omo-claude"
+export const PACKAGE_NAME = "@oh-my-opencode/omo-claude"
+export const CACHE_DIR_NAME = "omo-claude"
+export const EVENT_NAME = "omo_claude_daily_active"
+export const LEGACY_PARENT_PACKAGE = "oh-my-opencode"
+export const DEFAULT_POSTHOG_HOST = "https://us.i.posthog.com"
+export const DEFAULT_POSTHOG_API_KEY = "phc_CFJhj5HyvA62QPhvyaUCtaq23aUfznnijg5VaaGkNk74"
+
+export function getProductVersion(): string {
+  return packageJson.version
+}
diff --git a/packages/omo-claude/tsconfig.json b/packages/omo-claude/tsconfig.json
index 7a69d1222..71444b1e8 100644
--- a/packages/omo-claude/tsconfig.json
+++ b/packages/omo-claude/tsconfig.json
@@ -3,6 +3,8 @@
     "target": "ESNext",
     "module": "ESNext",
     "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "noEmit": true,
     "strict": true,
     "esModuleInterop": true,
     "skipLibCheck": true,