list_all_calendars

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

The readOnlyHint annotation already signals a safe read operation, and the description adds the return format and the flat-list nature, which is useful behavioral context. There is no contradiction, and the description provides value beyond the annotation without being verbose.

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 a single, well-structured sentence that front-loads the core action and scope, followed by a brief list of output fields and a usage note. No wasted words.

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 that an output schema exists and the description already lists the fields, the tool is fully specified. It also covers the primary use case for the returned data, making it complete for a parameter-free read-only list tool.

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 tool has zero parameters, so the schema provides no meaningful information. Per the baseline for 0-parameter tools, the description does not need to compensate. The description focuses on output semantics, which is appropriate.

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 lists every calendar across all connected accounts, with a specific verb ('List') and resource. It also enumerates the exact fields returned, distinguishing it from sibling tools like list_calendars by emphasizing the cross-account scope.

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?

Provides concrete guidance on when to use the resulting calendar id (as a sync-rule source/target or for a scheduling page). It does not explicitly contrast with list_calendars, but the 'across all connected accounts' phrasing implies the appropriate context for this tool.

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