Agent Interoperability Engineer

HushOne, Inc.; Kirkland (WA); Hybrid; USD 120,000 - 190,000; Full time

Benefits offered by this job

Stock options

401(k) with company match

Health, dental & vision insurance

Gym membership

Job summary

HushOne, Inc. is hiring a senior engineer to design and implement versioned MCP and A2A integrations alongside standard APIs, emphasizing robust failure handling and cross-system interoperability.

You will enable discovery, capability negotiation, authentication, and task status management while maintaining conformance tests and a comprehensive support matrix. We operate with an office presence in Kirkland, WA, two garages, and a remote-friendly policy for flexibility around family needs;

Qualifications

• Protocol, API, or distributed application engineering.
• Handle version changes and partial failure deliberately, with examples.
• Design against systems controlled by other organisations without trusting them.
• Test interoperability rather than assuming it from a specification.

Responsibilities

• Implement versioned MCP and A2A integrations alongside ordinary APIs.
• Build discovery, capability negotiation, authentication, task status and error handling.
• Maintain conformance tests and a support matrix; a protocol handshake must never be treated as blanket permission.
• Demonstrate a local tool, an external service and an independent remote agent with explicit permissions and cancellation in the first 90 days.

Skills

Protocol engineering

API design

Distributed systems

Versioning strategies

Interoperability testing

Tools

Conformance testing

Public specifications

Job description

You make Private Agent One work with other agents and tools while keeping the user's authority intact. Everything on the other side of these connections is controlled by somebody else, changes without warning, and fails partially, so the interesting engineering is in the failure handling rather than the happy path.

The work:

Implement versioned MCP and A2A integrations alongside ordinary APIs. Build discovery, capability negotiation, authentication, task status and error handling. Maintain conformance tests and a support matrix; a protocol handshake must never be treated as blanket permission.

What good looks like:

In your first 90 days, demonstrate a local tool, an external service and an independent remote agent working through explicit permissions and cancellation.

Evidence we look for:

Bring protocol, API or distributed application engineering experience. Show how you handle version changes, partial failure and systems controlled by other organizations.

Required:

• Protocol, API, or distributed application engineering
• You handle version changes and partial failure deliberately, with examples
• You design against systems controlled by other organisations without trusting them
• You test interoperability rather than assuming it from a specification

Nice to have:

• MCP, A2A, or comparable agent interoperability rails
• You have written or implemented a public specification
• Contract or conformance testing

The exercise:

Design an adapter for a remote agent that supports task creation but cannot guarantee cancellation after execution begins.

How we work:

We work together in the office, five days a week, and you can be based at any of our garages: Kirkland Garage (Kirkland, WA); UAE Garage (Dubai, Dubai). We hire across the United States, India and the UAE. We are remote-friendly around family: if you need to work from home some days to look after the people you love, we arrange that with you one person at a time, and we encourage people to use it rather than tough it out.

Pay:

We publish what we pay. Indicative ranges by market and level are on our compensation page, and they are realistic going market rates rather than headline numbers. Wherever we hire we pay at least the local market rate, and for full-time roles our floor is a living wage, never the statutory minimum. Compensation is reviewed every year and on promotion.

Equity:

Every full-time teammate gets stock options. Four-year vesting with a one-year cliff, sized to role, level and impact, and confirmed in writing at offer. High performers earn refresh grants.

Bonus and commission:

An annual performance bonus tied to clear company and personal goals, indicatively 10 to 20 percent of base for non-sales roles. Customer-facing roles carry on-target earnings, typically a 50/50 split of base and variable, with uncapped commission and accelerators above quota.

Health and peace of mind:

Medical, dental and vision for you and your family, plus life and disability cover. We have chosen the highest plan tier available to us rather than the cheapest one that clears the bar, because the point of this is that you never have to think about it. The specific plan numbers are confirmed in your offer letter.

401(k) with company matching:

A 401(k) with a company match, so the years you spend here compound into something that is yours whatever happens next. The match formula is confirmed in your offer letter.

AI tokens:

A budget of AI tokens of your own, because a company that says you should own your AI cannot be the company that rations it. Use them on the work and on whatever you are curious about.

Gym, and the everyday things:

A gym membership, and a corporate benefits programme with its own app, where you redeem real discounts with a long list of retailers on the ordinary purchases of a life.

Family:

We are remote-friendly around your family, arranged one person at a time, and we would rather you took it than toughed it out.

Referrals:

Refer someone we hire full-time who stays a year and you get $1,000 plus $10,000 in referral stock-based equity, on top of your own package.