Decagon — Customer Engineer, Agent Builder (London)

Type: Full-time | On-site (5 days/week) | London Borough of Brent, GB Compensation: £110,000–£150,000 + competitive equity Hiring count: 1 Visa sponsorship: None available — see scoring notes (structured field vs. outreach template conflict; confirm with Contrario before submitting) Reports to: Not specified on role page

About Decagon

Decagon is the leading conversational AI platform, empowering brands to deliver concierge customer experiences — deploying AI agents across voice, chat, email, SMS, and every other channel to replace support tickets and hold music with faster resolutions. Public customers include Avis Budget Group, Cash App and Square, Chime, Oura Health, and Hunter Douglas. It is an in-office company built around values of Just Get It Done, Invent What Customers Want, Winner's Mindset, and The Polymath Principle.

Founded: 2023 | Team size: 201–500 (Series D+) | Total funding: not disclosed on role page Backing: a16z, Accel, Bain Capital Ventures, Coatue, Index Ventures Industry: Conversational AI / Customer Support (Contrario tag: Consumer Tech) Website: https://decagon.ai Office: London Borough of Brent, GB

Why Candidates Should Join

• Category-leading platform with elite backing: a16z, Accel, Bain Capital Ventures, Coatue, and Index Ventures, powering agents for Avis Budget Group, Cash App/Square, Chime, Oura, and Hunter Douglas.
• Ground-floor on a brand-new org: the Agent Builder team was stood up earlier this year and is only 7–8 people in seat — real influence over how the team and Decagon's agent-building platform evolve.
• Genuine technical depth, not a CS seat: ~50/50 (up to 60/40) split of hands-on build (agentic logic, guardrails, integrations, eval frameworks) and customer-facing delivery, owning enterprise agent builds end-to-end.

Intake Call Summary

• No intake transcript available. The role page includes an Intake Video (Contrario × Decagon) but no text summary was provided in the copied HTML. Pull the video summary in a follow-up if intake detail is needed for scoring.

The Role

The Customer Engineer, Agent Builder is a post-sales, deployed engineer who owns end-to-end execution of AI agent builds for strategic enterprise customers — a highly technical delivery role split roughly 50/50 (or 60/40) between hands-on build and customer-facing engagement, depending on where each customer sits in its lifecycle. It sits inside a newly formed Agent Builder org (stood up earlier this year, 7–8 in seat) working in tight feedback loops with Agent PMs, Agent Success, Engineering, and GTM. Travel is rare.

What You'll Be Doing

• Own end-to-end architecture and execution of AI agent builds for enterprise customers — systems design and scoping through implementation, evaluation, and production deployment.
• Design and engineer the core agentic logic governing agent behavior, plus layered guardrails and supervisory controls for safe, compliant, predictable performance across non-deterministic outputs.
• Architect, build, and test integrations with customer systems (data pipelines, CRMs, ticketing systems) — the tools, APIs, and workflows needed for reliable deployment at scale.
• Interface with senior technical stakeholders at customers to define success criteria and system requirements, and drive technical delivery against timelines.
• Diagnose, debug, and resolve probabilistic and technical failures via root-cause analysis, and design evaluation and regression-testing frameworks that guard against performance drift.

Tech stack: Python (core); LLM / AI-agent tooling (prompting, evaluation, guardrails, workflow design); enterprise integrations (CRMs, ticketing systems, data pipelines, APIs).

Requirements

• 3 to 5 years technical customer-facing experience, post-sales
• Strong Python proficiency (hard requirement)
• CS or adjacent quantitative degree preferred
• LLM / AI agent build experience a plus

Green Flags

• Software engineer or forward-deployed engineer pivoting intentionally into customer-facing, post-sales delivery
• Strong, demonstrable Python ability with end-to-end integration work, comfortable coding without AI assistants
• Track record of delivering production-grade customer solutions requiring structured execution, testing, and iteration
• Clear communicator who can be walked into a room with senior executives without hand-holding
• CS degree from a strong program and hands-on experience building with LLMs or AI agents (prompting, evaluation, guardrails, tooling)

Red Flags

• Wants to pivot toward pre-sales rather than own post-sales technical delivery
• Weak or unproven Python, or reliance on AI coding assistants to produce working code
• Purely operational or IT-management background that does not transfer to hands-on engineering

Red Flags card was collapsed ("Show More") when copied — additional Red Flags exist beyond these three. Re-copy with the card expanded to complete this list.

Role Details

• Salary — £110,000–£150,000
• Equity — Competitive equity
• On-site policy — In-office, 5 days per week
• Visa sponsorship — None available (confirm with Contrario — see scoring notes)
• Employment type — Full-time
• Location — London Borough of Brent, GB

Required Candidate Q&A (Contrario submission form)

1. Phone Number
2. LinkedIn
3. Where did you go for college?
4. Are you excited to work in-office five days a week?
5. How did you hear about Decagon?
6. Are you legally authorized to work in the United Kingdom?
7. Will you now or in the future require visa sponsorship to work in the United Kingdom?

Interview Process

The Contrario pipeline lists twelve stages:

Stage 1 — Pending Approval — Candidates awaiting initial approval. Stage 2 — Application Review Stage 3 — Qualified / Holding Stage 4 — Recruiter / HM Screen Stage 5 — Initial Screen Stage 6 — Take Home Stage 7 — Onsite — Includes live Python assessment (no AI coding assistants permitted). Stage 8 — Debrief Stage 9 — Reference Check Stage 10 — Closing Stage 11 — Offer Stage 12 — Hired — Candidate accepts and starts.