plugmyagentTen minutes from now, you will ask your agent something it cannot answer from training data, and it will go fetch the real answer from a live API. A chatting agent is a toy. A working agent has tools. This guide connects the first one.
Pick a setup track on the guides page (10 minutes), then come back here. This guide works with whichever agent you choose.
01The finish line: what "working" looks like
Right now your agent chats. After this guide, it acts. You will ask "what is the temperature in Berlin right now" and it will go get the number from a live weather API instead of guessing from memory.
That gap, between answering from memory and fetching live data, is the entire skill. Everything else on this site is a variation of it.
"What is the current temperature in Berlin?" If the answer is a live number, you are done. If it says "Berlin is usually around...", it guessed. Section 05 fixes that in one sentence.
02Minutes 0 to 2: pick a boring API
For the 10-minute path, pick an API that needs no signup and no key. In the catalog, these carry the no signup effort badge. No forms, no waiting for a key email, nothing between you and a working test.
- Open the catalog and look for the no signup badge.
- Pick one you understand. Weather, crypto prices, jokes, IP lookup. If you know what it should return, you will know instantly whether it worked.
- Copy the endpoint URL from the API page. That long https address is the tool's address. You hand it to your agent in the next step.
Your first API should be boring. You are testing the plumbing, not building the product. Fancy comes later, after the pattern is proven.
03Minutes 2 to 4: the only three moves
Every API on this site connects the same way. Three moves, no exceptions:
●1. Get access
Copy the endpoint. Grab a key only if the API asks for one. Yours does not, which is why you picked it.
●2. Connect it
Tell your agent the tool exists: its address and what it returns. Plain words work.
●3. Test it
Ask one question only this API can answer. Live data back means it worked.
Keys, plug-ins, and libraries are all fancier versions of these three moves. Learn them here and you already know most of every setup on the site.
04Minutes 4 to 7: hand the tool to your agent
Your agent needs two things: the address (the endpoint URL you copied) and a description of what comes back. Open wherever your agent manages tools. It is usually called Tools, Integrations, Plugins, or Actions. Every agent has one.
Add it like this, using a real keyless weather API as the example:
Tool name: Current weather Address: https://api.open-meteo.com/v1/forecast?latitude=52.52&longitude=13.41¤t=temperature_2m Use it when: I ask about weather or temperature anywhere. It returns: JSON with the current temperature in Celsius.
If your agent takes tools as a chat message instead of a settings screen, send it exactly that text. If it has a tools screen, paste the address into the URL field and the rest into the description. Same information, either door.
You are not programming. You are delegating. Brief it the way you would brief a person: here is the tool, here is when to use it, here is what good looks like. Agents are fluent in plain words.
05Minutes 7 to 9: run the test
Ask the one question:
"What is the current temperature in Berlin?"
It answers with a specific number, in Celsius, that matches the real world right now. Check it against any weather site if you like. A live number means the tool fired. You have a working agent.
"Berlin is usually around 15 degrees this time of year" means it guessed without calling the tool. Fix it in one sentence: "No. Use the weather tool I just gave you and read the number from its response." Then ask again.
06Minute 9 to 10: make it yours
You now know the three moves. Add a second tool, a fun one this time: a joke API, a crypto price, the space station location. Same three moves, second rep. Two working tools means the pattern is yours, not luck.
And when you are ready for APIs that need a key, that is just move 1 with one extra step. Section 07 covers it in 60 seconds.
●Free API keys
Most of the catalog. One extra step: the key travels in the request header. The 60-second version ↓
●MCP servers
For agents that speak MCP: tools install with one command and a config block. Walkthrough W03 does it in 5 minutes →
●Libraries
JavaScript components install with npm and import in one line. Browse the components →
07The 60-second key version
Your second API will probably ask for a free key. Get it from the provider's site (free tier, no card on this catalog's listings), then send it in the request header. Three patterns cover nearly every API on earth:
curl -H "Authorization: Bearer YOUR_KEY" https://api.example.com/v1/data
curl -H "x-api-key: YOUR_KEY" https://api.example.com/v1/data
curl "https://api.example.com/v1/data?key=YOUR_KEY"
Your API's page on this site shows which pattern it uses. Tell your agent the same way as before, plus one line: "Send my key in the Authorization header."
Keys live in your agent's settings or secure vault. Never in a chat message, never in a screenshot, never in code you share. If a key leaks, revoke it and make a new one. Section 09 has the full rules.
08When it breaks: the 3-minute fix list
Something will go wrong once. It is almost always one of these five, and each takes under a minute to fix.
The key is missing, wrong, or in the wrong header. Re-copy it from the provider dashboard and check the pattern in section 07.
The endpoint URL has a typo. Compare it character by character with the API page. One wrong letter is enough.
You asked too fast. Free tiers are generous but not infinite. Wait a minute and try again.
It did not call the tool. Say "use the [name] tool" explicitly, naming it. Agents sometimes need the nudge.
The API refused a direct browser call. Have your agent call it instead, or route it through a tiny server. This one is never your fault.
09Key hygiene: the five rules
- Keys live in settings or the vault. Your agent's secure settings, or an environment variable. That is the entire list of approved homes.
- Never in chat, screenshots, or shared code. If you would not print it on a t-shirt, do not paste it there.
- One key per project. If one leaks, you revoke one, not everything.
- Leaked means revoked. The moment a key escapes, delete it at the provider and make a new one. Do not debate it.
- Free tier, calendar reminder. If a key came with a trial, set a reminder before it ends. Surprise bills are a choice.
Three moves: get access, connect it, test it. You did it in ten minutes with a boring weather API. The same three moves connect every listing on this site. Go collect tools.
Next: your first MCP server
The plug-in version of what you just did: install the official Fetch MCP server with one command, five minutes, no API keys.
002Then: the intermediate guide
From Tasks to Systems: memory that matters, connected tools, schedules that stick, and five copy-paste plays for your newly working agent.