Senior Python Engineer

Senior Python Engineer – Agent Runtimes & MCP
Location: Remote, with at least five hours of daily overlap with US Central and UK working hours
Duration: Initial six months; extension likely

Role Overview

First 90 Days — Key Focus Areas

These are initial priorities, not a fixed backlog. Focus areas may evolve as new agentic commerce capabilities emerge.

• Set up the blueprint’s verticals across Messages API, Agent SDK, and Managed Agents runtimes. Run test and verification suites and maintain fork compatibility.
• Integrate Agent Trust into StorefrontBackend and MerchantBackend, including session-start identity binding, cart and checkout trust checks, native result/error mapping, per-hook failure policies, PII-free decision logging, and outcome reporting.
• Build and test the storefront MCP server integration for Managed Agents behind an authenticating gateway, supporting vault credentials and signed identity claims.
• Develop an Experian MCP server with advisory tools and a companion skill for the commerce-builder Claude Code plugin.
• Write merchant integration guides and measure adoption effort through files changed, lines changed, prompt bytes, gates, and time to the first verified session.
• Implement OAuth token exchange under RFC 8693 with an enterprise identity provider, using audience-scoped downstream tokens without passing through the user’s token.
• Embed trust verification into AWS-hosted agent runtimes, such as Bedrock worker agents or Lambda/ECS services, with enforcement in application code outside the model.
• Build a shopping-agent evaluation harness covering tool calls, purchase correctness, prompt injection, incorrect items, and overspending, with reproducible CI runs.
• Develop backend services for regulated financial-services use cases, including typed APIs, audit logging, permissible-use checks, and idempotent operations.

Required Qualifications

• Five or more years building production Python microservices for modern SaaS backends.
• Strong experience with asyncio, typed Python, pytest, and ruff.
• API security experience covering OAuth 2.0 client credentials, on-behalf-of/token exchange flows, JWT issuance and verification, JWKS rotation and caching, and secrets handling.
• Microservices experience, including service-to-service authentication and structured error/result handling across service boundaries.
• Ability to reason about fail-open versus fail-closed behaviour within latency constraints.
• Ability to understand unfamiliar or unmaintained codebases quickly and support technical claims with module and line references.
• Ability to deliver independently from written acceptance criteria.

Preferred Qualifications

• Production OAuth token exchange experience under RFC 8693, including audience validation, scope narrowing, and confused-deputy prevention.
• Production AWS experience with Lambda or ECS, IAM, and Secrets Manager.
• Experience shipping tool-using LLM agents through Claude Messages API or Agent SDK.
• Understanding of prompt caching and static-prefix requirements.
• Experience building or integrating authenticated MCP servers using streamable HTTP.
• Experience building or extending LLM evaluation harnesses.
• Familiarity with Claude Managed Agents, Claude Code plugins/skills, and Bedrock, Vertex, or Foundry routing.
• E-commerce experience covering carts, product variants, and checkout hand-off.
• Node.js 22 experience for example storefront integrations.

Key Deliverables

The agent-trust-commerce Python package, a Managed Agents gateway variant, an Experian MCP server, a commerce-builder companion skill, a merchant integration guide, and a retail demonstration.

Travel Needs

Occasional travel to partner or merchant sites may be required.