Cline (VS Code 4.1.x, CLI 3.x) runs hook files named after their event from ~/.cline/hooks/ or .cline/hooks/. A hook's contextModification reaches the model on TaskStart, UserPromptSubmit, PreToolUse and PostToolUse in VS Code, and on PreToolUse and PostToolUse in the CLI. That would make it the next harness for plugin/cline/ after OpenCode.
Its payload names taskId, agent_id and parent_agent_id, but neither the model nor a transcript path. Per-message tokens are in ~/.cline/data/sessions/<id>/<id>.messages.json as metrics{inputTokens, outputTokens, cacheReadTokens, cacheWriteTokens}. VS Code also needs its "Enable Hooks" setting turned on.