Apps Script MCP

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

With no annotations provided, the description carries full burden for behavioral disclosure. While 'Send' implies a write operation, it doesn't disclose critical behaviors: whether this requires specific Gmail permissions, if there are rate limits, whether the email is sent immediately or queued, or what happens on failure. The description lacks essential context for a mutation tool.

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

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

The description is reasonably concise with a clear purpose statement followed by parameter details. However, the parameter explanations are somewhat minimal, and the structure could be improved by grouping related parameters or adding usage examples. It's functional but not optimally organized.

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

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

Given this is a mutation tool with 7 parameters, 0% schema description coverage, no annotations, but with an output schema, the description is moderately complete. It covers basic purpose and parameters but lacks behavioral context and usage guidance. The output schema existence means return values don't need explanation, but other gaps remain significant.

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

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

The description provides a parameter list with brief explanations that add meaningful context beyond the schema's 0% coverage. It clarifies that 'to' accepts comma-separated addresses, 'cc' and 'bcc' are optional, and 'html' determines body format. This compensates well for the schema's lack of descriptions, though it doesn't cover all parameter nuances like email format validation.

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

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

The description clearly states the verb ('Send') and resource ('a Gmail message'), making the purpose immediately understandable. It distinguishes from sibling tools like 'get_gmail_message_tool' and 'search_gmail_messages_tool' by focusing on sending rather than retrieving. However, it doesn't explicitly contrast with other email-related tools since none exist in the sibling list.

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

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

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites like authentication, nor does it specify scenarios where this tool is appropriate versus other communication methods. The sibling tools include various Google services, but no explicit comparison is made.

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