Day 26 of 28 · OpenClaw Challenge
Building Your Own Tools
⏱ 8 min
📊 Advanced
This is the power move. Everything you've done so far uses tools that already exist — email, calendar, web, files. But what about your tools? Your company's internal dashboard? Your proprietary API? Your custom workflow?
Today you'll learn to build tools that make your agent work with anything.
What is a custom tool?
A tool is just a function the agent can call. It has a name, a description (so the agent knows when to use it), and an action (what it actually does).
For example:
Name: check_inventory
Description: "Check the current inventory levels for a product in our warehouse system"
Action: Calls your warehouse API and returns the stock count
That's it. Once this tool exists, the agent can use it just like email or calendar. You say "check inventory for Widget Pro" and the agent calls your tool.
Knowledge Check
What are the three parts of a custom tool?
A
A login page, a database, and a report
B
A name, a description (so the agent knows when to use it), and an action (what it does)
C
A frontend, a backend, and a database
D
An input, a process, and an output
Every tool has a name (what it's called), a description (how the agent decides when to use it), and an action (what it actually does when called). The description is crucial — it's how the agent matches your request to the right tool.
MCP — the universal connector
Remember MCP from Day 4? Model Context Protocol is the standard for building tools. It's like USB for AI agents.
Any tool built with MCP works with any MCP-compatible agent. That means your custom tool doesn't just work with OpenClaw — it works with any AI agent that supports MCP.
The MCP standard handles the boring parts: how the agent discovers the tool, how it passes inputs, how it gets results back. You just write the actual logic.
I want to build a tool that checks our company dashboard for sales numbers.
Great idea! Here's what we'll create:
**Tool name**: company_dashboard
**Description**: "Query the company sales dashboard for metrics like revenue, deals, and pipeline"
**Action**: Calls your dashboard API endpoint
I need two things from you:
1. Your dashboard's API URL (or how to access the data)
2. What metrics you want available (revenue, deals, pipeline, etc.)
Once I have those, I can build the tool for you.
The API is at dashboard.ourcompany.com/api and I want revenue, active deals, and churn rate.
Tool built ✓
You can now ask me things like:
— "What's our revenue this month?"
— "How many active deals do we have?"
— "What's our current churn rate?"
I'll pull live data from your dashboard every time. Want to test it?
📊 Live from your dashboard:
💰 Revenue (Feb): $158,000
🤝 Active deals: 34
📉 Churn rate: 2.1%
Tool is working perfectly. It's now available in all your conversations and workflows.
↻ Replay conversation
Knowledge Check
After building the dashboard tool, where can the agent use it?
A
Only for scheduled reports
B
Only when you specifically tell it to use the dashboard tool
C
Only in the conversation where you built it
D
In any conversation, workflow, or automation — it's now part of the agent's permanent toolbox
Once a tool is built, it's available everywhere — in real-time conversations, scheduled automations, and workflows. The agent can also combine it with other tools, like including dashboard data in your morning briefing.
You don't need to be a programmer
Here's the thing people assume: "Building tools must require serious coding skills." Not necessarily.
Many custom tools are config-only. You provide an API URL, authentication, and what data you want. OpenClaw builds the tool for you.
For more complex tools (custom logic, data transformation, multi-step processes), some coding helps. But the MCP framework handles most of the complexity — you write the business logic, MCP handles the plumbing.
And the community has hundreds of pre-built tools you can install. Chances are, someone already built what you need.
Knowledge Check
Do you need programming skills to create a custom tool?
A
Yes — all tools require advanced programming
B
No — tools are always built through a visual interface
C
You can never build your own tools
D
It depends — simple tools (API wrappers) need minimal or no coding, complex tools need some
Simple tools that wrap an existing API can often be created with just configuration. Complex tools with custom logic need some coding. And many tools are already built by the community — check there first before building from scratch.
Ideas for your first custom tool
Here are the tools that OpenClaw users build most often:
Internal dashboard — pull metrics from your company's dashboard or analytics platform
CRM integration — read and update customer records in your specific CRM
Proprietary database — query your company's internal database for information
Internal wiki — search and read your company's knowledge base or wiki
Deployment pipeline — trigger deployments, check build status, roll back releases
Start with the tool you'd use most often. Build one, test it, then build the next.
Final Check
What should you do before building a custom tool from scratch?
A
Build a prototype in a spreadsheet first
B
Get a computer science degree
C
Check the community ecosystem — someone may have already built what you need
D
Ask your boss for permission
The MCP ecosystem has hundreds of pre-built tools contributed by the community. Before spending time building from scratch, check if someone already built a connector for your tool. You might just need to install and configure it.
🛠️
Day 26 Complete
"If a tool doesn't exist, build it. If it does exist, install it. Either way, your agent can connect to anything."
Tomorrow — Day 27
Sharing Your Agent
Your agent is powerful. Let's share it with your team so everyone benefits.