Dsh Cost Guard

Key features

• Actual usage, not prompt-size guessing — reads inputTokens, outputTokens, cacheReadTokens, and cacheWriteTokens from DSH session events.
• Host half listens to agent/request and session/event, attributes usage to turns, rolls up subagents, and exposes private RPC handlers.
• No outbound requests, telemetry, credential reads, or API key storage.
• Live and glanceable — keeps task cost and token mix beside the composer where decisions happen.
• Subagent-aware — rolls subagent usage into the active root-session turn.