Cartpanda · Agent Harness
Control plane preview · v0.1
claude-opus-4-7 onlinePlano, TX · Delaware · main@sha:a1b2c

Honest scope note. This harness preview runs on Vercel with the Claude API so you can click through it in 60 seconds. In your stack it becomes a Hono service in front of your agent runners, wired into your Neon + Drizzle + Temporal Cloud + ECS Fargate pipeline. TypeScript end-to-end. No Python, no n8n, no glue-layer.

For Renato · Cartpanda & Fluveo

Constrain.
Track.
Synthesize.
Merge.

A four-module preview of the control plane your agents need before a single line of generated TypeScript touches a charge in your Hyperswitch connector. Deterministic AST-level guardrails on monetary code, live PROGRESS.md synchronisation across git worktrees, Temporal saga synthesis from a one-liner spec, and a human-in-the-loop merge queue that holds the pager until a senior clicks Approve. No LLM math, no parseFloat on cents, no empty catch.

→ 01 FinTech AST guardrail→ 02 PROGRESS.md state tracker→ 03 Temporal saga architect→ 04 HITL merge queue
01

FinTech AST Guardrail

Every PR authored by an agent passes through a deterministic pre-commit gate before it ships into your Hono handlers. parseFloat on monetary values, empty catch blocks, missing Zod parse at the boundary — the gate catches them all and replies with the corrected code. The LLM is a pair, not a cowboy.

Business value · Zero parseFloat on a charge. Ever.

agent_output.ts · pending reviewbranch: agent/hyperswitch-charge
17 lines · TypeScript · ESM
guardrail · agent.trace
›
// hit Run Pre-Commit Gate to validate the snippet
02

PROGRESS.md State Tracker

Each agent writes to its own worktree and commits progress to a shared PROGRESS.md. The orchestrator tails it live and coordinates merge readiness. No shared mutable state, no Slack pings, no cross-agent contention. Just file-based source of truth — the same pattern your team already uses, instrumented.

Business value · See four agents converge in real time. Exactly your internal workflow.

orchestrator · agent.trace
›
// click Start feature to drive the orchestrator
PROGRESS.md0 / 9 tasks
# Feature: Add 3DS refund flow (spec v1)
> orchestrator: claude-opus-4-7
> worktrees: 4 parallel
## agent_db
branch: feat/3ds-refund-db
[ ]Drizzle migration for refunds.three_d_secure_token
[ ]Down migration + rollback test
[ ]Update charges.ts schema with typed reference
## agent_api
branch: feat/3ds-refund-api
[ ]POST /v1/refunds/3ds handler with Valibot guard
[ ]Wire idempotency middleware (IDM-004)
## agent_test
branch: feat/3ds-refund-test
[ ]Vitest integration suite: happy path + timeout retry
[ ]Mock Hyperswitch 3DS callback
## agent_saga
branch: feat/3ds-refund-saga
[ ]Temporal workflow with compensation on timeout
[ ]Activity timeouts per ADR-008
03

Temporal Saga Architect

One-line spec in, typed Temporal.io workflow out: proper activity timeouts, compensation on every side-effect, typed input / output. The diagram is generated from the same response so the Lead Architect can audit the saga shape before the agent writes a single line of production code.

Business value · From one sentence to a reviewable saga. Seconds, not an afternoon.

saga.spec
claude-opus-4-7 · max 2500 tokens
// submit a saga spec to see the workflow + diagram.
04

Human-in-the-Loop Merge Queue

Every PR authored by an agent lands here with the guardrail matrix attached. A senior reviews the diff, the LLM reasoning note, the activity timeouts — and clicks Approve. No merges without a human signature. Blocked PRs are automatically re-prompted with the failing rule.

Business value · Your pager stays quiet. Your SOC-2 auditor stays happy.

agent_harness.merge_queue4 awaiting a human
cartpanda/payments · main
idtitleagentdiffconfstatus
PR-412Add idempotency key to Hyperswitch connectorclaude-code+62 -1175%needs review
PR-411Temporal saga: webhook replay handler for Stripecodex+88 -491%needs review
PR-410Refund saga for Brazilian Pix network timeoutscursor+104 -2263%blocked
PR-409Drizzle schema migration: add refund_reason to chargesdevin+28 -196%approved
PR-408Add Valibot guard on /v1/charges POST endpointclaude-code+34 -888%needs review