Missive MCP

missive_update_contacts

DestructiveIdempotent

Update existing contacts by providing their UUIDs and the fields to change. Replaces entire arrays such as 'infos' or 'memberships' when supplied.

Instructions

Update one or more contacts by UUID (PATCH /contacts/:id1,:id2,...). Each object in contacts[] must include its id; only the attributes you supply are changed. WARNING: passing infos or memberships REPLACES the whole array — omitted items are deleted, so read-merge before writing. Idempotent.

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": {
      "contacts": "<contacts>"
    },
    "name": "missive_update_contacts"
  }
}

Input Schema

Name	Required	Description	Default
`contacts`	Yes	One or more contacts to update; each must include its `id`.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 26, 2026

TDQS

A4.6/5.0

Behavior5/5

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

The description adds significant behavioral context beyond annotations, such as partial update behavior and the array replacement warning, which aligns with the destructiveHint annotation. No contradictions.

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 concise with three well-structured sentences, front-loading the purpose and method, followed by important behavioral warnings. No unnecessary information.

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?

The description covers key aspects like partial updates, array replacement, and idempotency, but does not mention the response format or error conditions. Given the complexity and no output schema, it is mostly complete.

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

Parameters4/5

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

Schema coverage is 100%, but the description adds value by explaining the id requirement and the semantics of partial updates and array replacement, enhancing understanding of the single parameter.

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?

The description clearly states the tool updates one or more contacts by UUID, with a specific verb and resource, and distinguishes itself from sibling tools like missive_create_contacts and missive_list_contacts.

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?

The description provides clear context for updating contacts, including the requirement for IDs and warning about array replacement. It does not explicitly list alternatives or when not to use, but the purpose is well-defined.

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

Deploy Server