CallMCP — Phone Call MCP Server

Launch Call Campaign

launch_call_campaign

Destructive

Start or resume an existing outbound call campaign so Kai begins calling its leads. Needs campaign_id and agent_id (an agent assigned to the same business), the calls:write scope and an admin role in the business. Queues the campaign's pending calls within its call windows; real people get phone calls once it runs. A queued result does not mean any call was answered or completed. pause_call_campaign stops it. Not for email campaigns.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "campaign_id": "<campaign_id>",
      "agent_id": "<agent_id>"
    },
    "name": "launch_call_campaign"
  }
}

Input Schema

Name	Required	Description
`agent_id`	Yes	The agent that places the calls. Must belong to the same business.
`business_id`	No	Business ID. Required when the token can reach more than one business.
`campaign_id`	Yes	The call campaign, from list_campaigns.

Output Schema

Name	Required	Description
`error`	No	Present when success is false
`action`	No
`queued`	No
`success`	Yes	Whether the tool completed successfully
`campaign_id`	No
`paused_jobs`	No
`reset_leads`	No
`sequence_id`	No
`cancelled_attempts`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 12, 2026

TDQS

A4.7/5.0

Behavior5/5

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

The description adds substantial behavior beyond annotations: real people receive phone calls, pending calls are queued within call windows, and a queued result does not mean a call was answered or completed. This complements the destructive and open-world annotations by explaining real-world effects and result semantics.

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?

The description is compact and front-loaded: the first sentence states the core action, then prerequisites, side effects, result caveat, and the stopping alternative follow in order. Every sentence carries useful operational information with no filler.

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

Completeness5/5

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

For a destructive, open-world mutation with an output schema and full annotation coverage, the description covers the critical context: required parameters, authorization scope, real-world calling impact, queuing behavior, and result interpretation. Nothing essential is missing for correct invocation.

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 description coverage is 100%, so the input schema already documents all three parameters, including that agent_id must belong to the same business and campaign_id comes from list_campaigns. The description adds only a small amount by repeating campaign_id and agent_id as required, which is adequate but not beyond the schema baseline.

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?

States a specific verb and resource: start or resume an outbound call campaign so Kai begins calling leads. It explicitly excludes email campaigns and names pause_call_campaign as the stopping counterpart, so an agent can distinguish it from siblings without opening another schema.

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

Usage Guidelines5/5

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

Explains when to use it (start or resume an existing call campaign) and names pause_call_campaign as the alternative for stopping. It also gives authorization prerequisites, the calls:write scope, and admin role, which are selection conditions rather than mere parameter restatement.

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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