mcp-calendly

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

The annotations already declare destructiveHint=true, indicating this is a mutation operation. The description adds minimal behavioral context beyond this—it doesn't specify whether cancellation is reversible, if notifications are sent, or what happens to associated data. With annotations covering the safety profile, a 3 is appropriate as the description adds little extra value.

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, efficient sentence with zero waste. It's front-loaded with the core action and resource, making it easy to parse quickly. Every word earns its place without redundancy.

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 tool's complexity (a destructive operation with 2 parameters), the description is minimally adequate. It lacks output details (no output schema exists) and behavioral nuances, but annotations cover the destructive nature. For a simple cancel action, it meets basic needs but could be more informative about side effects or usage context.

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?

Schema description coverage is 100%, with both parameters ('event_uuid' and 'reason') fully documented in the schema. The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints. Baseline 3 is correct when the schema does all the heavy lifting.

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 action ('Cancel') and resource ('a scheduled Calendly event'), making the purpose immediately understandable. However, it doesn't differentiate this tool from potential alternatives like deleting or rescheduling events, which could exist in a broader Calendly API context.

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 (e.g., needing an existing scheduled event), exclusions, or relationships with sibling tools like 'get_event' or 'list_scheduled_events' that might help identify events to cancel.

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