Apps Script MCP

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states this is an update operation but doesn't mention important behavioral aspects: what permissions are required, whether changes are reversible, how conflicts are handled, rate limits, or what the response looks like. For a mutation tool with zero annotation coverage, this leaves significant gaps in understanding its behavior.

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 well-structured and appropriately sized. The first sentence states the core purpose, followed by a clear 'Args:' section with bullet-point parameter explanations. Every sentence adds value, though the 'all_day' explanation could be slightly clearer. The structure helps users quickly understand both what the tool does and how to use it.

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 the complexity (10 parameters, mutation operation) and the presence of an output schema (which reduces need to describe return values), the description is moderately complete. It covers all parameters but lacks behavioral context (permissions, side effects) and usage guidance. For a tool with no annotations and significant parameters, it should provide more context about when and how to use it effectively.

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?

With 0% schema description coverage, the description provides substantial value by explaining all 10 parameters in the 'Args' section. It clarifies semantics like 'calendar_id (default: "primary")', 'start_time in ISO format', 'attendees as comma-separated list', and the conditional logic for 'all_day'. This compensates well for the schema's lack of descriptions, though some format details (like exact ISO format) could be more precise.

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 tool's purpose: 'Update an existing calendar event.' It specifies the verb ('update') and resource ('calendar event'), making the function immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'create_event_tool' or 'delete_event_tool' beyond the obvious verb difference, which prevents a perfect score.

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. While the name 'update_event_tool' implies it's for modifying existing events (versus 'create_event_tool' for new ones), the description doesn't mention prerequisites, constraints, or sibling relationships. There's no explicit when/when-not usage advice or references to other tools.

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