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

Annotations declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is already covered. The description adds real behavioral context beyond that: automatic weather fetch within ~16 days, the returned event id, and that '' clears priority.

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?

Front-loaded with purpose, then required params, then optional fields and side effects. Dense but each clause carries information; only mildly long.

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?

For an 11-param mutation tool with no output schema, the description covers the essential behaviors (required fields, return value, weather side effect, downstream handoff). It stops short of documenting every optional URL param, but nothing critical for correct invocation is missing.

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 coverage is 73%, and the description compensates by specifying the date format (YYYY-MM-DD), that startTime 'picks the forecast hours', and by grouping the optional fields (logistics notes, prep notes, priority, target). This adds meaning beyond the bare schema, especially for the undocumented 'date' and 'description' properties.

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?

States a specific verb+resource ('Create an event the athlete is preparing for') and enumerates concrete examples (race, key ride, FTP test) plus the target system (Blocks calendar). This clearly distinguishes it from siblings like update_event, delete_event, and list_events.

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?

Gives an explicit trigger ('Use when the athlete describes one in chat') and routes the agent onward to set_event_notes for detailed prep, and clarifies the GPX route is added in the app rather than here. It doesn't contrast against update_event for pre-existing events, but the trigger condition is clear.

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