Every engineer’s first reaction to “you need guardrails around your AI agents” is “I can build that.” And you can. The question is whether you should, and what that decision actually costs.
What “Build Your Own” Actually Requires
A minimal viable gateway for AI coding agents needs these components. Here’s a rough estimate of the engineering time each takes:
Proxy layer: intercept and route all agent API calls. Days.
Authentication and agent identity: unique credentials per agent, token management. Days.
Policy engine: load policies, evaluate rules against requests, enforce deny-by-default. One to two weeks.
Audit logging: structured logging, immutable storage, queryable retrieval. About a week.
Approval workflows: trigger on risky actions, route to Slack, handle responses, timeouts and retries. One to two weeks.
Cost tracking: token budgets per agent, alert thresholds, automatic session termination. About a week.
Session management: start, stop, kill, session state, heartbeats. Days.
Dashboard: live session view, log search, policy editor. Two to three weeks.
Total first version: a few months of a senior engineer’s time, before testing, documentation and the edge cases you’ll discover in production.
The Hidden Costs
The estimate above is for the first version. What gets underestimated:
Ongoing maintenance. Policies change as your access patterns change. Integrations break when vendors change their APIs. Someone owns this.
Security issues. A system that handles credentials and access is security-sensitive. When a vulnerability is found, someone needs to fix it fast.
Features you don’t build. The features you skip in v1 become the ones you wish you had in production.
Opportunity cost. And all of this is plumbing. You still need people to use the agents to build the software your business actually needs.
A Different Option: Don’t Build the Plumbing at All
Building a gateway makes sense if you have an engineering team that will run AI agents every day. If what you actually want is working business software, there’s another path.
Sentrely is a managed AI team, backed by real engineers, that builds, ships and monitors production-grade software in accounts you own. Our engineers deploy and supervise the AI employees. Your team asks our agent in your Slack to build, ship and monitor production-grade software. Automated safety checks run on every change, important changes get human sign-off, your data and files have a 35-day rewind, and you have a named account manager and on-call support.
| Factor | DIY Gateway | Sentrely |
|---|---|---|
| What you get | Infrastructure your engineers maintain | Software built and shipped for you |
| Who you need on staff | Engineers to build and run it | No developers required |
| Safety checks | Whatever you build | Automated checks on every change |
| Human review | Whatever you build | Engineer sign-off on important changes |
| Undo | Whatever you build | 35-day rewind on data and files |
| Where the software lives | Your accounts | Your own hosting and code accounts |
| Support | Your team | Named account manager and on-call support |
When DIY Makes Sense
There are real cases where building your own is the right choice:
- You have an engineering team that will run agents every day
- Your requirements are highly specific and nothing off the shelf fits
- You have security rules that prohibit third parties
- The gateway is your core product
If none of those apply and you’d rather not build and run this yourself, book a free 30-minute call and we’ll tell you honestly whether Sentrely fits.