Feature Request: WakaTime Integration for Time Tracking

Summary

Add WakaTime integration to Codex CLI to track coding time spent in sessions. This would send heartbeats to the local wakatime-cli when files are read/written, enabling developers to track their AI-assisted coding time alongside regular coding activity.

Motivation

• Consistency with Claude Code: Claude Code already has WakaTime support, making this a natural addition for Codex CLI
• Developer productivity tracking: Many developers use WakaTime to track their coding time across different tools and projects
• AI coding metrics: WakaTime supports --ai-line-changes flag to track lines added/changed by AI assistants

Proposed Implementation

I have a working implementation ready on my fork that includes:

Configuration

Opt-in via ~/.codex/config.toml:

[wakatime]
enabled = true
# Optional overrides:
# cli_path = "~/.wakatime/wakatime-cli"
# project = "my-project"

Architecture

• New codex-wakatime crate with WakaTimeTracker struct
• Rate limiting: 1 heartbeat per minute per file (writes bypass limit)
• Integrates with SessionServices in codex-core
• Hooks into file operations via ToolEmitter::emit() for patch apply events
• Spawns wakatime-cli in background (non-blocking)

WakaTime CLI invocation

~/.wakatime/wakatime-cli \
  --entity /path/to/file \
  --plugin "codex-cli/1.0" \
  --project "project-name" \
  --write  # for write operations

Files Changed

• codex-rs/wakatime/ (new crate)
• codex-rs/Cargo.toml (workspace)
• codex-rs/core/Cargo.toml
• codex-rs/core/src/config/types.rs
• codex-rs/core/src/config/mod.rs
• codex-rs/core/src/state/service.rs
• codex-rs/core/src/codex.rs
• codex-rs/core/src/tools/events.rs

Testing

All existing tests pass, plus 3 new unit tests for the wakatime crate.

Happy to submit a PR once this feature request is approved.