[v1.5] Cost tracking per account/orchestrator

[webdevtodayjason]

Background

Power-user feedback (via Grok): no visibility into per-account / per-orchestrator cost. Users want to know what each session is costing them in the same way they can see rate-limit headroom.

Signal sources

Anthropic returns input/output token counts in response headers. Claude Code already writes per-session JSONLs at ~/.claude-<alias>/projects/<project>/<session>.jsonl containing every message with token metadata. The ~/.claude/rate-limit-events.log already captures session metadata. So the data is there — the dashboard just doesn't surface it.

Two-tier ship

Tier 1 — observation only

• Parse session JSONLs for input/output token counts
• Multiply by Anthropic's published per-model rates
• Add a "Cost today" / "Cost this week" card to each account on the dashboard
• HTTP API: GET /api/billing returns per-account / per-session breakdown
• MCP tool: mcp__subctl__billing so agents can self-report cost

Tier 2 — subctl billing CLI

• subctl billing — show today + this week aggregated
• subctl billing --account <alias> — filter
• subctl billing --session <name> — per-orchestrator
• subctl billing --csv — exportable

Non-goals

• Cost projection / budgeting alerts (could be v1.6)
• OpenAI pricing for Codex (separate, Tier 1.5 once Codex provider is GA)

Verdict

Should ship in v1.5. Medium effort, high visibility. Sets up budgeting features later.