KaiCalls

Make Call

make_call

Destructive

Initiate an outbound voice preview via a KaiCalls AI agent. This lets the owner hear Kai, but it is preview only and never proves inbound routing or advances activation. Pass an idempotency_key to make the request safely retryable.

Input Schema

TableJSON Schema

Name	Required	Description
`to`	Yes	Phone number to call (E.164 format, e.g. +19085551234)
`name`	No	Caller/lead name (optional)
`context`	No	Call context or reason (optional)
`lead_id`	No	Existing lead ID to associate (optional)
`agent_id`	Yes	KaiCalls agent ID to use for the call
`first_message`	No	Override the agent greeting message (optional)
`idempotency_key`	No	Client-chosen key that makes this call exactly-once: retries with the same key never place a second call (optional but recommended)
`connector_activation_call`	No	True only for the one-time connector activation call the recipient explicitly requested in this conversation. This is not permission for marketing, SMS, or future calls.

Output Schema

TableJSON Schema

Name	Required	Description
`call`	No
`error`	No	Present when success is false
`success`	Yes	Whether the tool completed successfully
`replayed`	No
`intent_id`	No
`preview_only`	No
`idempotency_key`	No
`counts_toward_activation`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedSep 10, 2026

addedInput schema / properties / connector_activation_call

Added value: +{
+  "description": "True only for the one-time connector activation call the recipient explicitly requested in this conversation. This is not permission for marketing, SMS, or future calls.",
+  "type": "boolean"
+}

addedOutput schema / properties / counts_toward_activation
```
Added value: +{
+  "type": "boolean"
+}
```
addedOutput schema / properties / preview_only
```
Added value: +{
+  "type": "boolean"
+}
```

Changed4 schema fields changedJul 21, 2026

addedInput schema / properties / idempotency_key

Added value: +{
+  "description": "Client-chosen key that makes this call exactly-once: retries with the same key never place a second call (optional but recommended)",
+  "type": "string"
+}

addedOutput schema / properties / idempotency_key
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / intent_id
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / replayed
```
Added value: +{
+  "type": "boolean"
+}
```

AddedJun 22, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations mark this as mutating/destructive, and the description goes further: it performs a real outbound call, is preview-only, has activation limitations, and is retry-safe with an idempotency key. This is meaningful behavioral context beyond what readOnlyHint/destructiveHint already communicate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the core action, and zero filler. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers the crucial distinction between preview call and inbound routing/activation, which is the main risk of misuse. It doesn't discuss post-call outputs or prerequisites, but those are minor given output_schema exists and the core constraint is stated.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description does highlight idempotency_key behavior in prose, but that guidance is already present in the parameter's schema description, so it adds no new semantic information.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Opens with exact action and resource ('Initiate an outbound voice preview via a KaiCalls AI agent'), then immediately disambiguates scope ('preview only' — not inbound routing or activation). An agent can tell what this tool does and what it does not do.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Clearly frames when this tool is appropriate ('owner hear Kai', preview only) and explicitly states it never proves inbound routing or advances activation. It does not name an alternative sibling tool for activation verification, so it misses the top bar for routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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