GuidesAI agents
Give your agent Tools
Let the AI agent look up customers, open tickets and do other work while the caller is on the line: start from a template or build your own, then attach it to the agent.
A Tool is something the AI agent can do during a call, such as finding the caller’s account or opening a ticket. You build Tools in Tool Builder, publish them, and attach them to an agent.
- Where
- Build > Tool Builder, then the agent’s Business Tools
- Plans
- Every plan. Custom Tools: 3 on Starter, 10 on Pro, 25 on Scale (see Plan limits)
- Takes
- A few minutes from a template
How it fits together
- Actions are the single steps a Tool can take: Crulon’s own, such as “find a contact by phone number”, or a Custom Action that calls your API.
- A Tool puts one or more Actions together, with a description the agent reads to decide when to use it.
- The agent gets the Tools you attach under Business Tools.
Handing a call to a person, ending a call and answering from your documents aren’t Tools. They’re set on the agent, in Call Handling and Knowledge.
Start from a template
Templates are ready-made Tools. Open Build > Tool Builder, select New tool, and pick one. Two work in every workspace:
| Template | What the agent can do |
|---|---|
| Look up customer | Find the caller in your contacts from the number they’re calling from, or a number or account number they give |
| Create ticket | Open a ticket for your team with a subject, a description and a priority, linked to the caller |
Apps you install add their own templates, under From your Apps. Each App’s page in Integrations lists what its Tools do. To connect a system of your own, build a Custom Action and use it in a Tool of your own.
Each template shows a badge for what it does: Reads data, Writes data or Changes things. Templates you can’t use yet are greyed out with the reason, such as App required, with a Fix this link where there’s something to fix.
Templates under Not available yet are planned, and can’t be used.
Create the Tool
Select Use this template. Keep the Name or change it: it’s the name the agent calls the Tool by, in lowercase letters, numbers and underscores. Select Create draft.
Publish it
Open the ⋯ menu and select Test to try it (see Test a Tool). Then select Publish, and Confirm publish. Agents can only use published Tools.
Attach it to the agent
Open the agent in AI Studio > Agents, go to Business Tools and select Attach a Tool. Pick the Tool, then select Done.
Publish the agent
Select Publish on the agent. The Tool goes live with it.
A Tool made from a template stays in step with Crulon: when we improve the Action behind it, your Tool picks it up. If you change its steps, it becomes yours to maintain, and Crulon asks before it does.
Build your own Tool
Select New tool, then Start from blank. A Tool is drawn as steps joined by lines, which Crulon calls nodes:
| Node | What it does |
|---|---|
| Input | What the agent fills in when it uses the Tool, such as an order number. Each field has a name, a type, whether it’s required, and a description for the agent |
| Action | Runs one published Action. Map each of its values to an input, a fixed value, or something an earlier step returned |
| Condition | Checks something an earlier step returned, such as whether a customer was found, and carries on down true or false |
| Return | What the agent gets back. Return only what it needs to answer the caller |
Input
What the problem is
Filled in by the agent from what the caller said
Action
Look up customer
By the number they’re calling from
Condition
Customer found?
Action
Create ticket
Linked to the customer
Return
The ticket number
Return
Not found
The agent asks for their account number
Steps run one at a time, in order, and only down the branch a Condition picks. If a step fails, the Tool stops there. A Tool can have up to 64 nodes, and has 30 seconds to finish.
Some values Crulon fills in itself from the call, such as the caller and the customer they’ve been matched to. They show as Filled in automatically, and the agent can’t set or change them, so the agent can’t change which customer a Tool works on.
Under Tool details, write the Description for the agent: what the Tool does and when to use it. Select Save draft, then Validate from the ⋯ menu to check it before you publish.
Warning
Never paste a password or API key into a node. Save it as a credential on a Custom Action.
Test a Tool
In the editor, open the ⋯ menu and select Test. Tests run the last saved draft.
- Sample data answers each Action with made-up data. Nothing is called and nothing changes.
- Live run runs the real Actions, so it can create, change or delete real data. Tick I understand this executes real actions and may change data first.
For a Tool that works on the caller, pick a customer under Call as to test as them. A Tool that needs the caller’s yes can’t finish a live test: the yes only happens on a real call. Test the rest with sample data.
Settings for each agent
Select the gear on an attached Tool to set how this agent uses it. Changes apply to this agent only; the Tool and other agents keep theirs.
| Setting | Starts as | What it does |
|---|---|---|
| Instructions | The Tool’s description | What this agent reads about the Tool. Up to 2,000 characters |
| Confirmation | The Tool’s own text, if any | What the agent should check with the caller before it runs. Up to 1,000 characters |
| Speech while running | The Tool’s default | A line the agent says as the Tool starts, such as “One moment while I take care of that.” Or Off for none |
| Minimum time before answering | Off | Makes the agent wait at least this long, up to 15 seconds, so a quick answer doesn’t sound rushed. 3 to 6 seconds sounds like a person checking |
| Give up after | 20 seconds | How long to wait for the Tool: 5 to 30 seconds |
| If it’s still working, say | Nothing | A line said once, after 8 seconds of silence to start |
| What the caller hears | Crulon’s sentences | What the agent says when the Tool fails or takes too long, one sentence each |
A badge on the row, such as Custom speech or Gives up 15 s, shows what you’ve changed.
On a call
- 01
The agent decides to use it
From the Tool’s description and what the caller has said.
- 02
It checks with the caller
“I’ll open a job for the no-heat problem at 27 Cedar Court. Shall I go ahead?”
- 03
The Tool runs
With your line while running, if you set one. The agent waits up to 20 seconds.
It works
The agent answers from what the Tool returned.
It fails or takes too long
The agent tells the caller, using your sentence for that outcome, and carries on.
Checking with the caller first
For a Tool that changes something, the agent is told to say what it’s about to do and wait for a clear yes. The AI asks in its own words, guided by the Confirmation text. Crulon adds one check: the Tool won’t run until the agent marks that the caller agreed, and if it tries without asking, it’s sent back to ask.
Templates that ask first say so when you create them: “The caller has to confirm before it runs.” Create ticket doesn’t ask: write a Confirmation on the agent if you want it to. See Changes that need the caller’s yes for where the text comes from.
Classic and Live agents
On the Classic engine the agent waits for the Tool before it answers, and says your lines word for word. On the Live engine it keeps talking while the Tool runs and says your line in its own words; If it’s still working, say isn’t used.
Test with Talk in browser
Warning
Tools run for real in test calls
In Talk in browser, Tools do real work unless you turn on Use sample data for tools. Testing as a customer with Call as acts on their real account: anything a Tool creates or changes, it does for real.
Turn on Use sample data for tools to rehearse a call without changing anything. The agent still asks for a yes where it would on a real call.
Versions
Publishing makes a version that can’t be changed. To change a Tool, edit the draft and publish again; the Versions tab lists every version, and Rollback republishes an old one as a new version.
Each agent keeps the version it was attached with, so publishing a new version doesn’t change an agent until you choose to. When a newer version exists, the agent’s Tool row says so: select Re-pin, then publish the agent. Check for updates in Business Tools looks for all of them at once.
Deleting a published Tool archives it: agents stop using it, and it stays under Show archived.
See what a Tool did
In Conversations, a call’s details show each Tool the agent used: what it sent, what came back, how long it took and what the caller was told. A failed run says why, such as The tool took too long or Caller not identified yet. People who can’t see transcripts see this under Tool activity.
App activity, in Build > App activity, lists what your installed Apps did and what your AI agents did through them, kept for 12 months.
Plan limits
Your plan’s Custom Tools limit is 3 on Starter, 10 on Pro and 25 on Scale. It counts the Custom Actions you build, the ones that call your own API:
- Each Action counts once, however many versions it has.
- Drafts count, and so do Actions you’ve deleted after publishing them.
Tools themselves aren’t limited, and neither are templates or the number of Tools on one agent.
If something goes wrong
Check the Tool is published and enabled, attached under Business Tools, and that you published the agent. Then make its Instructions say plainly when to use it: “Use this when the caller reports a problem with their service.”
The Tool works on the customer, but the agent hadn’t found them. Attach Look up customer too, so the agent finds the caller first.
The agent tried to run a Tool that changes something without the caller’s yes, so Crulon sent it back to ask. That’s expected; check the agent then asked and ran it.
The Tool didn’t answer within Give up after. For your own API, check how long it takes in the Custom Action’s test. For a write, the change may still have gone through.
The reason shows on the tile, such as App required or Setup needed. Select Fix this where it’s shown.
Each Action node needs a published Action. Publish your Custom Action first, then pick it.
You’ve built as many Custom Actions as your plan allows. Deleting a draft frees its place, but published Actions you’ve deleted still count. Otherwise, upgrade.
Last updated 18 Oct 2026