Summary

Read-only operator panel for Kora's monthly Agent SDK credit ladder per R4.1 §9.6 — current burn against the $200/mo pool, active rung, downshift state, deferred-for-cost tickets, and reconciliation history. Pairs with future KR-P2-K (cost-state runtime + reconciliation).

This is the 5th panel in the proven stub-first pattern (#26 OPS → flipped in #35, #31 SEA, #37 CONTROL, #45 BOOT). The pattern is empirically known to flip cleanly.

Endpoint (kora_cli/web_server.py)

GET /api/cost-state — returns current + rate_limit_pulse + deferred_tickets[] + reconciliation_history[] + stub: true. No POST/PUT/DELETE; cost-rung transitions are automatic in KR-P2-K's runtime and the "extra-usage OFF" hard cap is an Anthropic-console toggle.

No raw credentials in the response shape — dollar amounts + model tier + ticket IDs only. Enforced by test_no_credential_shaped_keys_in_response (regex-walks the payload for token / secret / api_key / password / bearer / authorization keys; expects zero matches).

Frontend (web/)

pages/CostStatePage.tsx — 4 sections:

1. Burn summary — big $87.43 / $200.00 headline, rung pill, horizontal progress bar with tick marks at 75/90/100% and fill colour matched to active rung. Projection callout color-tones based on projected_end_of_period_usd / credit_pool_usd:
   • > 1.0 → red "Projected to exceed $200 by month-end"
   • > 0.9 → amber "On track to cross the 90% rung"
   • else → green "On track within budget" (the stub's 43.7%-used / $128 projection lands here, per the §7 smoke note)
2. Active rung & downshift — rung pill + effective-model-tier badge + downshift indicator + extra-usage hard-cap status (destructive alert if extra-usage is ON)
3. Rate-limit pulse — requests + tokens bars showing remaining/limit ratio, tone-coded
4. Deferred + reconciliation — collapsible; default-expanded when there are deferred tickets so operator sees them immediately. Deferred ticket entries link to /sea-tickets.

lib/api.ts — new CostRung type + 4 interfaces (CostCurrent, RateLimitPulse + RateLimitWindow, DeferredTicket, ReconciliationEntry, CostStateResponse). Reuses existing ModelTier + Criticality from prior panels.

App.tsx — /cost-state route + nav entry (DollarSign icon) between /boot-status and /kora-control.

Flip-over plan

When KR-P2-K lands and CostStateHolder.current() + .rate_limit_pulse() + .recent_reconciliations(limit=N) + a substrate scan for state == deferred_cost_limit tickets exist, swap get_cost_state body to project from those and drop the stub flag. The page itself doesn't change.

Test plan

• tests/kora_cli/test_web_server_cost_state.py — 11/11 green, covers all 10 §5 scenarios + extra contract guard (hard_stop_100 ⇒ extra_usage_off must be True; never silently accept a hard-stop with the Anthropic console cap turned off)
• test_web_server_{boot_status,kora_control,sea_tickets,cron_profiles,host_header,mcp,gateway_identity}.py — 67/67 still green (78 total)
• npx tsc -b on web/ — clean
• npx vite build on web/ — clean
• §8 grep checks (5 total): STUB banner present, endpoint registered, zero write-side routes, zero credential-shaped keys in payload, ModelTier + Criticality each defined exactly once (reused, not duplicated)
• Manual smoke: navigate to /cost-state, verify STUB banner renders, verify burn-summary progress bar shows tick marks at 75/90/100% with green fill, verify projection callout reads green "On track within budget" for the stub's 43.7%-used case, verify deferred-tickets section auto-expands because the stub has 1 deferred ticket

Dependency notes

• KR-P2-K (future CC#1 bucket) builds the cost-state runtime + reconciliation
• CostStateHolder.current() + .rate_limit_pulse() + .recent_reconciliations(limit=N) + a substrate query for deferred_cost_limit tickets are the accessors that flip this from stub to real

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