gsuite

google-gmail_modify_message

Modify labels on a Gmail message: add or remove labels, mark as read or unread.

Instructions

Modify labels on a message (add/remove labels, mark read/unread)

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": {
      "id": "<id>"
    },
    "name": "google-gmail_modify_message"
  }
}

Input Schema

Name	Required	Description
`id`	Yes	Message ID to modify
`userId`	No	User's email address or 'me' for authenticated user
`addLabelIds`	No	Comma-separated list of label IDs to add
`removeLabelIds`	No	Comma-separated list of label IDs to remove

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.4.0Jul 13, 2026

TDQS

B3.3/5.0

Behavior3/5

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

No annotations provided, so description carries full burden. It discloses the main actions (add/remove labels, mark read/unread) but does not mention permissions, idempotency, or side effects like triggering mail filters.

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

Conciseness4/5

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

Very concise single sentence that front-loads the purpose. Could include a bit more detail without losing conciseness, but currently no wasted words.

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

Completeness2/5

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

With 4 parameters and no output schema or annotations, the description is too minimal. It does not explain the effect of adding/removing labels concurrently, error cases, or behavior when no labels specified.

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 has 100% coverage of parameter descriptions. The description adds no extra meaning beyond the schema; baseline 3 is appropriate.

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 modifies labels on a message, including adding/removing labels and marking read/unread. It distinguishes from sibling tools like send, delete, or list messages.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus alternatives, such as when to use create_draft or send_message. No exclusions or prerequisites mentioned.

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