LoopEngine vs Claude Code, Codex and agent SDKs

Claude Code, Codex, the Claude Agent SDK, the OpenAI Agents SDK and LoopEngine all run an AI model in a loop with tools. They are built for different jobs:

• Claude Code and Codex are general-purpose agents you work with. They started with code and now also research, write documents, work through spreadsheets and use your apps through MCP connectors. You give them a task, follow along, and check the result.
• Agent SDKs are parts. They give a developer the loop, tool calling and hooks, and leave the rest to build.
• LoopEngine runs agents that do routine business work on their own, such as answering customer emails, triaging alerts and checking expenses, and asks a person before anything risky.

The difference isn't what the model can do. Often it's the same model. It's whose agent it is and how it runs: a personal assistant working with you, a kit for building your own, or a team's agent doing a job on its own, inside rules the team sets.

What's built in, and what you build

First, a fair qualification: little in this post is impossible with Claude Code, Codex or an SDK. They are extensible, and their makers describe the agent harness as infrastructure developers can build their own applications on. The difference is what each gives you out of the box, and what you would have to build, host and maintain yourself.

The first three rows are where they're equal. The rest is the application around the agent: the scheduling, the approvals, the permissions and the shared setup. That's the part LoopEngine builds for business jobs, so you don't have to. The sections below go through it.

Runs with nobody watching

Claude Code and Codex are at their best with a person working alongside: you give a task, follow along, steer and check. You can script them to run headless or on a timer, but then the hosting, the credentials, the retries and what happens when the agent needs someone's approval are yours to build and keep running.

A LoopEngine agent is set up once and then works on its own:

• On a schedule, such as every morning at 9, or every 10 minutes to answer new emails.
• When another system calls it, through its HTTP API: your helpdesk on a new ticket, your monitoring on an alert, your site on a form submission.

Nobody needs to be online for it to run. When it reaches something it may not do alone, it asks, then carries on once someone answers.

Asks the right person, where they already are

When Claude Code or Codex wants to do something that needs permission, it asks the person using it, in that session. That works when you're the one who decides. It doesn't work for a refund at 3am, or an expense that only the finance lead may approve.

In LoopEngine, a tool set to Ask me sends a request to the people who own that decision:

• In Slack, Lark, email or Telegram, with the details and one-click Approve and Reject.
• Or to a webhook, so your own system can decide or show it in your app.
• To the right person: the support lead for refunds, finance for payments, on-call for production changes.

The agent waits for the answer. Approve, and the action runs and the agent carries on. Reject, and the action never happens and the run stops there.

Waits days, not seconds

An approval often takes longer than a process stays up. Someone approves the refund the next morning, after the server has restarted twice.

LoopEngine approvals are durable. A paused run is saved, holds no open connection while it waits, and continues from the same point whenever the answer arrives, minutes or days later.

With an SDK you can build this, but it's real work. You need a store for each paused run, a way to resume it from a webhook, guards so an action never runs twice, and expiry for answers that never come. In-memory approvals, the usual starting point, are lost on the first restart.

Permissions per tool, per agent

Claude Code and Codex have permission settings too, but they belong to one person's setup: which files and commands they may use, and which connected tools they may call, in that person's session. LoopEngine's are the team's rules for a job, set once on the agent and applied to every run:

• Each tool gets a rule. Looking up an order is Allow, issuing a refund is Ask me, deleting a customer is Never.
• Each agent gets only the tools for its job. Connect Stripe once, then give the support agent "look up a charge" and "refund", and the finance agent "list payouts".
• Rules are enforced by LoopEngine, outside the model. The agent can't talk its way past Ask me or Never, whatever is in the email it's reading.

That last point matters most for agents that read customer messages. A prompt-injected email can change what a model wants to do. It can't change what the agent is allowed to do.

Made for the team that owns the job

Anyone can use Claude Code or Codex, but each person sets up and runs their own. An SDK-built agent needs developers for every change. In LoopEngine, an agent belongs to the team and the people who own the work run it:

• Templates set up common jobs in a minute: customer emails, refund approvals, incident triage, expense checks, lead follow-up.
• Workflows: describe a job in a sentence or two, and LoopEngine plans the steps, shows where it will ask first, and creates the agent with its schedule off until you're ready.
• A browser console to change an agent's instructions, tools, permissions and schedule, and to chat with it to test.
• One shared setup. The apps, keys, rules and approvers are set once for the job, not copied onto each person's laptop.

Developers still have a place. They connect your company's systems as apps or private abilities, call agents from your own products, and can self-host the whole thing.

Call it from your own systems

Every agent has an HTTP endpoint. Your helpdesk, back office or website sends it a message with a workspace API key:

POST https://<your-workspace>.loopengine.app/agents/<agent-name>/messages
Authorization: Bearer lek_...
Content-Type: application/json

{ "message": "Draft a reply to ticket 4821" }

The answer comes back in the response. If the agent stopped to ask for an approval, the response is 202 with pending: true, and the run continues once someone decides.

Any model, and your own servers

Claude Code and Codex use their own vendor's models. LoopEngine lets you choose a model for each agent: OpenAI, Anthropic, Gemini, DeepSeek, Kimi, GLM and others, with reasoning effort where the model supports it. A routine triage agent can run on a fast, cheap model while a refund agent uses a stronger one.

The runtime's source is available. Use LoopEngine Cloud, or run the same agents on your own servers with npm create loopengine. Your agents are plain files, so they move with you.

What they do better

Use the right tool for each job:

• Working with you on anything: for a one-off task you want to steer, such as research, a report, a spreadsheet or a tricky email, Claude Code and Codex are the better fit. You're there, you decide as you go, and nothing needs setting up.
• Coding: reading a codebase, changing many files, running tests and fixing what fails is still where they're strongest.
• Full control: if agents are your product and you want every part your own way, an SDK gives you the parts.

Use them together

These tools fit together. A common setup:

1. A developer uses Claude Code or Codex to write a private ability that wraps your order system.
2. They install it in LoopEngine, give it to a customer-service agent, and set refunds to Ask me.
3. The agent answers customer emails around the clock, and the support lead approves refunds from Slack.

Want to try it? Start from a template, describe a workflow, or read For developers to self-host.