diff --git a/packages/omo-codex/plugin/components/telemetry/AGENTS.md b/packages/omo-codex/plugin/components/telemetry/AGENTS.md
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+# Repository Conventions
+
+Conventions for human contributors and AI agents working on this component.
+
+## Style
+
+- Terse technical prose. No emojis in commits, issues, PR comments, or code.
+- TypeScript strict mode. No `any`, no `@ts-ignore`, no `@ts-expect-error`, no enums.
+- ESM modules with `.js` suffix in runtime import paths.
+- Tabs for indentation. Double quotes for strings.
+- Tests use vitest with `#given .. #when .. #then` descriptions or plain `// given / // when / // then` body comments.
+
+## Commands
+
+- `npm install` - install dependencies.
+- `npm test` - run vitest once.
+- `npm run typecheck` - strict TypeScript check.
+- `npm run check` - type check, biome, and build.
+- `npm run build` - emit `dist/`.
+- `node dist/cli.js hook session-start < fixture.json` - smoke-test the SessionStart hook.
+
+## Constraints
+
+- No Bun APIs. Runtime is Node only because Codex launches plugin hooks with Node.
+- The single hook handler is `runSessionStartHook`. Do not add new hook handlers without also wiring them in `hooks/hooks.json` and `plugin/hooks/hooks.json`.
+- Telemetry MUST be silent on every failure path. The CLI MUST exit 0 with empty stdout even when PostHog construction, capture, or shutdown throws.
+- Telemetry MUST be daily-deduplicated. Adding a new event type requires a new state file slot, not removal of the existing dedup.
+- Hook output MUST stay empty (no `additionalContext`, no `systemMessage`). This component is observability-only and MUST NOT inject context into the Codex conversation.
+- Constants in `src/product-identity.ts` MUST stay byte-equivalent with `packages/omo-codex/src/telemetry/product-identity.ts`. The cross-package equivalence test will fail otherwise.
+- Do not couple this component back to omo internal source paths beyond what `cross-package-equivalence.test.ts` already asserts at the constants layer.
+
+## Don'ts
+
+- No `git add -A` or `git add .`. Stage only the files you changed.
+- No `git commit --no-verify`. No force pushes. No history rewriting on shared branches.
+- No new network calls. PostHog is the only allowed sink.
+- No new env vars without README + privacy-policy update.
diff --git a/packages/omo-codex/plugin/components/telemetry/README.md b/packages/omo-codex/plugin/components/telemetry/README.md
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+++ b/packages/omo-codex/plugin/components/telemetry/README.md
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+# codex-telemetry
+
+Codex plugin component that emits a single anonymous daily-active event (`omo_codex_daily_active`) to PostHog whenever a Codex session starts.
+
+The event is sent **at most once per UTC day per machine**. It uses a SHA256-hashed installation identifier derived from `omo-codex:${hostname}` and never sends the raw hostname. PostHog person profiles are explicitly disabled.
+
+## Hook Wiring
+
+The component registers a single `SessionStart` hook:
+
+```json
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "node \"${PLUGIN_ROOT}/dist/cli.js\" hook session-start",
+            "timeout": 5
+          }
+        ]
+      }
+    ]
+  }
+}
+```
+
+The aggregate `plugin/hooks/hooks.json` mounts this hook alongside `rules` and `ultrawork` so all three fire in parallel at the start of every Codex session.
+
+## What Is Captured
+
+A single PostHog `capture` call with:
+
+- `event: "omo_codex_daily_active"`
+- `distinctId: sha256("omo-codex:" + hostname)`
+- `properties`:
+  - `platform`, `product_name`, `package_name`, `package_version`
+  - `runtime` (`"node"`), `runtime_version`
+  - `source: "plugin"`, `reason: "session_start"`
+  - `$os`, `$os_version`, `os_arch`, `os_type`
+  - `cpu_count`, `cpu_model`, `total_memory_gb`
+  - `locale`, `timezone`, `shell`, `ci`, `terminal`
+  - `day_utc` (today's UTC date)
+  - `$process_person_profile: false`
+
+The component never sends prompt contents, file contents, API keys, raw hostnames, or any user-identifying data.
+
+## Opt-Out
+
+Set any of the following environment variables before launching Codex:
+
+```bash
+# Codex-only opt-out
+export OMO_CODEX_DISABLE_POSTHOG=1
+export OMO_CODEX_SEND_ANONYMOUS_TELEMETRY=0
+
+# Global opt-out (covers both omo and omo-codex)
+export OMO_DISABLE_POSTHOG=1
+export OMO_SEND_ANONYMOUS_TELEMETRY=0
+```
+
+When any of these is set the component creates a no-op PostHog client and exits without any network call.
+
+## Daily Deduplication
+
+The component writes a small JSON state file at:
+
+```
+$XDG_DATA_HOME/omo-codex/posthog-activity.json
+# or, when XDG_DATA_HOME is unset:
+~/.local/share/omo-codex/posthog-activity.json
+```
+
+containing `{ "lastActiveDayUTC": "YYYY-MM-DD" }`. If the stored day matches today (UTC), the hook returns without sending anything. The file is written atomically via `rename(2)`.
+
+## Failure Behavior
+
+Every telemetry path is wrapped in `try`/`catch`. The hook always exits 0 with no stdout output, even when PostHog construction, capture, or shutdown fails. Codex session startup is never blocked or slowed by telemetry failures.
+
+## Endpoint Overrides
+
+| Variable | Default |
+|----------|---------|
+| `POSTHOG_HOST` | `https://us.i.posthog.com` |
+| `POSTHOG_API_KEY` | shared `omo-codex` project key |
+
+## Development
+
+```bash
+npm install
+npm test           # vitest (in-process + subprocess CLI smoke)
+npm run typecheck
+npm run build      # tsc -> dist/
+npm run check      # typecheck + biome + build
+```
+
+The component shares its product identity constants with the `@oh-my-opencode/omo-codex` CLI installer. Drift between the two implementations is guarded by `packages/omo-codex/src/telemetry/cross-package-equivalence.test.ts`.
+
+## Privacy
+
+See [the omo Privacy Policy](https://github.com/code-yeongyu/oh-my-openagent/blob/dev/docs/legal/privacy-policy.md) for the full disclosure.
diff --git a/packages/omo-codex/plugin/components/telemetry/biome.json b/packages/omo-codex/plugin/components/telemetry/biome.json
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index 000000000..5aa1a0dcc
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+++ b/packages/omo-codex/plugin/components/telemetry/biome.json
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+{
+	"$schema": "https://biomejs.dev/schemas/2.4.15/schema.json",
+	"linter": {
+		"enabled": true,
+		"rules": {
+			"recommended": true,
+			"style": {
+				"noDefaultExport": "error",
+				"noEnum": "error",
+				"noNonNullAssertion": "error",
+				"useImportType": "error",
+				"useConst": "error",
+				"useNodejsImportProtocol": "off"
+			},
+			"complexity": {
+				"useLiteralKeys": "off"
+			},
+			"suspicious": {
+				"noExplicitAny": "error",
+				"noTsIgnore": "error",
+				"noControlCharactersInRegex": "off",
+				"noEmptyInterface": "off"
+			}
+		}
+	},
+	"formatter": {
+		"enabled": true,
+		"formatWithErrors": false,
+		"indentStyle": "tab",
+		"indentWidth": 3,
+		"lineWidth": 120
+	},
+	"files": {
+		"includes": ["src/**/*.ts", "test/**/*.ts", "vitest.config.ts", "!**/node_modules/**/*", "!**/dist/**/*"]
+	},
+	"overrides": [
+		{
+			"includes": ["vitest.config.ts"],
+			"linter": {
+				"rules": {
+					"style": {
+						"noDefaultExport": "off"
+					}
+				}
+			}
+		}
+	]
+}
diff --git a/packages/omo-codex/plugin/components/telemetry/package.json b/packages/omo-codex/plugin/components/telemetry/package.json
new file mode 100644
index 000000000..27f9e7249
--- /dev/null
+++ b/packages/omo-codex/plugin/components/telemetry/package.json
@@ -0,0 +1,56 @@
+{
+	"name": "@code-yeongyu/codex-telemetry",
+	"version": "0.1.0",
+	"description": "Codex plugin component that emits omo-codex anonymous daily-active telemetry on SessionStart.",
+	"type": "module",
+	"packageManager": "npm@11.12.1",
+	"license": "MIT",
+	"homepage": "https://github.com/code-yeongyu/oh-my-openagent",
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/code-yeongyu/oh-my-openagent.git"
+	},
+	"bugs": {
+		"url": "https://github.com/code-yeongyu/oh-my-openagent/issues"
+	},
+	"keywords": [
+		"codex",
+		"codex-plugin",
+		"omo",
+		"telemetry",
+		"posthog",
+		"hooks",
+		"daily-active"
+	],
+	"bin": {
+		"omo-telemetry": "./dist/cli.js"
+	},
+	"files": [
+		"dist",
+		"hooks",
+		"LICENSE",
+		"README.md",
+		"CHANGELOG.md"
+	],
+	"scripts": {
+		"build": "tsc -p tsconfig.build.json",
+		"test": "vitest --run",
+		"test:watch": "vitest",
+		"typecheck": "tsc --noEmit",
+		"lint": "biome check .",
+		"lint:fix": "biome check --write .",
+		"check": "tsc --noEmit && biome check . && npm run build"
+	},
+	"dependencies": {
+		"posthog-node": "^5.34.3"
+	},
+	"devDependencies": {
+		"@biomejs/biome": "2.4.15",
+		"@types/node": "^25.7.0",
+		"typescript": "^6.0.3",
+		"vitest": "^4.1.5"
+	},
+	"engines": {
+		"node": ">=20.0.0"
+	}
+}
diff --git a/packages/omo-codex/plugin/components/telemetry/tsconfig.build.json b/packages/omo-codex/plugin/components/telemetry/tsconfig.build.json
new file mode 100644
index 000000000..5b5bbcafd
--- /dev/null
+++ b/packages/omo-codex/plugin/components/telemetry/tsconfig.build.json
@@ -0,0 +1,12 @@
+{
+	"extends": "./tsconfig.json",
+	"compilerOptions": {
+		"allowImportingTsExtensions": false,
+		"declaration": true,
+		"outDir": "dist",
+		"rootDir": "src",
+		"noEmit": false
+	},
+	"include": ["src/**/*"],
+	"exclude": ["test/**/*"]
+}
diff --git a/packages/omo-codex/plugin/components/telemetry/tsconfig.json b/packages/omo-codex/plugin/components/telemetry/tsconfig.json
new file mode 100644
index 000000000..342229c02
--- /dev/null
+++ b/packages/omo-codex/plugin/components/telemetry/tsconfig.json
@@ -0,0 +1,27 @@
+{
+	"compilerOptions": {
+		"target": "ES2022",
+		"module": "Node16",
+		"moduleResolution": "Node16",
+		"lib": ["ES2022"],
+		"strict": true,
+		"exactOptionalPropertyTypes": true,
+		"noUncheckedIndexedAccess": true,
+		"noPropertyAccessFromIndexSignature": true,
+		"verbatimModuleSyntax": true,
+		"noImplicitOverride": true,
+		"noImplicitReturns": true,
+		"noFallthroughCasesInSwitch": true,
+		"noUnusedLocals": true,
+		"noUnusedParameters": true,
+		"esModuleInterop": true,
+		"allowImportingTsExtensions": true,
+		"skipLibCheck": true,
+		"forceConsistentCasingInFileNames": true,
+		"resolveJsonModule": true,
+		"useDefineForClassFields": false,
+		"types": ["node"],
+		"noEmit": true
+	},
+	"include": ["src/**/*", "test/**/*"]
+}
diff --git a/packages/omo-codex/plugin/components/telemetry/vitest.config.ts b/packages/omo-codex/plugin/components/telemetry/vitest.config.ts
new file mode 100644
index 000000000..c4fddb41c
--- /dev/null
+++ b/packages/omo-codex/plugin/components/telemetry/vitest.config.ts
@@ -0,0 +1,8 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+	test: {
+		environment: "node",
+		pool: "threads",
+	},
+});