# Hire an AI agent developer who tests the agent before handover

> Hire an AI agent developer: a one-page spec, tools limited to what you approve, a scored eval run of up to 50 cases before handover, and a fixed price.

Canonical: https://app369.com/service/hire-ai-agent-developer/

An AI agent build takes 10 business days and ships with a scored run of up to 50 eval cases. Simon Dziak builds it on your own model account, with tool access limited to the actions you approve.

The AI Feature or Agent Build is a fixed $2,500, and the 10 days start once the spec is agreed and repo access and test keys arrive. Want Claude to use your product instead? The MCP Connector for your SaaS is $2,500; ChatGPT needs OAuth sign-in, +$1,000.

Fixed prices

[**All fixed-price offers**](https://app369.com/fixed-price/)

- [$2,500**AI Feature or Agent Build**One LLM feature or agent wired into your app or tools, with an eval set that shows how well it works.**See scope and start**](https://app369.com/fixed-price/ai-feature-development/)
- [$2,500**MCP Connector for your SaaS**An MCP server over your existing REST API, so your product works inside Claude, and in ChatGPT with OAuth sign-in.**See scope and start**](https://app369.com/fixed-price/mcp-server-for-saas/)

Something else? [**Describe your project**](https://app369.com/contact/)

How the agent gets built

## **What an agent build covers**

- 01 ### **The simplest version that does the job** Anthropic’s guide separates workflows, “systems where LLMs and tools are orchestrated through predefined code paths”, from agents, which “dynamically direct their own processes and tool usage”, and recommends “finding the simplest solution possible, and only increasing complexity when needed”. The spec says which one your task needs, and why. [**AI Feature or Agent Build**](https://app369.com/fixed-price/ai-feature-development/)
- 02 ### **A one-page spec you approve first** The task, the inputs and outputs, the tools the agent may call and how success is measured, written down before any code.
- 03 ### **Tools limited to what you approve** The agent can call only the actions in the spec, and anything that writes data is gated. Anthropic recommends “extensive testing in sandboxed environments, along with the appropriate guardrails”, so the agent is tested on test keys first.
- 04 ### **An eval set before you ship** OpenAI’s guide says evals “test model outputs to ensure they meet style and content criteria that you specify”. You get up to 50 cases from your own examples and a scored run before handover, so you see how well it works instead of guessing.
- 05 ### **Logs and cost you can read** Prompts, tool calls and token cost are logged, and model usage is billed by your provider to your own account.
- 06 ### **Let Claude or ChatGPT use your product** The MCP docs call it “an open-source standard for connecting AI applications to external systems”. An MCP connector exposes up to 8 tools over the REST API you already have. Claude works with API-key sign-in; ChatGPT needs the OAuth sign-in add-on. [**MCP Connector for your SaaS**](https://app369.com/fixed-price/mcp-server-for-saas/) [**AI app development and integration**](https://app369.com/service/ai-integration/) [**How to build an MCP server**](https://app369.com/blog/how-to-build-an-mcp-server-2026/)

Before you hire

## **Questions to ask an AI agent developer**

Ask these of whoever you hire, App369 included, and get the answers in writing.

- **✓**### **Is this a workflow or an agent?** Fixed steps are more predictable and easier to test. Ask why the task needs the model to choose its own steps.
- **✓**### **How will you measure it?** Ask for the eval cases and a scored run before handover, and who reruns them after a prompt or model change. With App369, the scored run comes before handover.
- **✓**### **What can it change?** Ask which tools write data, what needs a person’s approval, and where it is tested before it touches real records.
- **✓**### **What will it cost to run?** Ask for token cost logged per run, on your own provider account, so the bill never surprises you.

- Claude API
- Gemini API
- MCP
- TypeScript
- Node.js

FAQ

## **Questions before you start**

<details>

<summary>**How much does it cost to hire an AI agent developer? **</summary>

App369 publishes fixed prices: the AI Feature or Agent Build is $2,500 for one feature or agent in 10 business days, and the MCP Connector for your SaaS is $2,500, with OAuth sign-in for ChatGPT at +$1,000. Model usage is paid to your provider directly.

</details>

<details>

<summary>**Can you build an AI feature that is not an agent? **</summary>

Yes. The same offer covers one LLM feature, such as a reply drafter or a document extractor, with the same spec, eval set and handover.

</details>

<details>

<summary>**Do you guarantee an accuracy score? **</summary>

No. The eval set shows how well the agent does on your own examples before you ship it, so you decide with real numbers. A guaranteed score is not part of the offer.

</details>

<details>

<summary>**Do you train or fine-tune models? **</summary>

No. The agent runs on the Claude or Gemini API, or another model API you already use, on your own provider account.

</details>

<details>

<summary>**What do I need to hand over? **</summary>

Examples of the task for the eval set, repo access and test keys. Keep production keys and passwords out of email: you add them in your own accounts.

</details>

<details>

<summary>**Do I need a call first? **</summary>

No. The spec and the build happen in writing by email. If you want to talk it through, consultations are paid: $100 per 15 minutes, paid upfront.

</details>

<details>

<summary>**Who does the work? **</summary>

Simon Dziak, who founded App369, does every part of the work, and builds the AI features and MCP server in Workspace369, App369’s own product.

</details>

### **Sources**

- [Anthropic: Building effective agents (Dec 19, 2024)](https://www.anthropic.com/engineering/building-effective-agents)
- [OpenAI docs: Evals guide](https://developers.openai.com/api/docs/guides/evals)
- [Model Context Protocol: What is MCP?](https://modelcontextprotocol.io/docs/getting-started/intro)

Not a fixed-price job?

## **Describe it and get a written quote**

Send what you need built or fixed. You get a written scope, a fixed price and a timeline; Simon replies by email, usually within one business day.

[**Describe your project **→](https://app369.com/contact/) [**Instant quote**](https://app369.com/instant-quote/)

Prefer a call? Consultations are $100 per 15 minutes, paid upfront.