A corporate booking platform with a policy-aware chat agent, in production.

The platform lets companies book business travel for their employees inside a travel policy. Travellers search flights and hotels, book, and follow each trip from a web app; administrators manage their company from admin and console pages. The same rules apply everywhere: booking statuses, which supplier serves which currency, the per-room adult cap, tax identity rules and which policy fields are enforced. The web app repeats those rules from contracts the API publishes, and checks its copy automatically, so the screen never promises something the API will refuse.

The API runs as Python Lambdas on AWS, with Postgres, Cognito sign-in, three travel supplier integrations, a payments provider, a credit ledger, and a renderer that produces tickets, vouchers and emails. A suite of about 10,700 automated tests covers it. Production deploys are refused for any commit staging has not run, and supplier production credentials are never used from a laptop.

The chat agent is a FastAPI and WebSocket service on ECS Fargate, built on the Claude Agent SDK with no built-in tools. Its only tools come from one in-process MCP server, each bound to the signed-in user's identity, and its read tools run under Postgres row-level security. Every turn is traced to a self-hosted Langfuse.

The agent has two tiers of evals: tool evals that check it calls the right tools correctly, and semantic scenarios graded by an LLM judge against a deployed agent. Before any US-dollar company is admitted, a scripted US-market eval runs the real model, prompt, tools and handlers against fixed API answers, with fixed-rule scoring and no LLM judge. It fails a reply on any rupee or Indian tax wording, on a dollar amount the tools did not produce, or on a day-first date, and checks that an over-policy approval is filed in dollars. A run costs about $0.40.

The web app, API and chat agent are in production for companies whose travel policy is set in rupees. US-dollar companies reach the agent only through a pilot allowlist, which is currently empty on both staging and production, so US use has not started. The platform's team and Plexe change the system through pull requests across separate repositories for the web app, API and agent. A unified supplier gateway for more suppliers and accounting connectors was planned, then archived at the design stage; it is not part of the live system.