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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description adds genuine value beyond them: the removal is partial (only today onward), the operation is two-phase with a safe preview, and library entries are affected alongside the calendar. It doesn't say whether the deletion is reversible or how the preview is reported, which keeps it below the top mark.

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?

Three short sentences front-load the effect and the safety protocol before the compact Args block. Every sentence carries distinct information; no restatement of the title or name.

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?

A destructive, two-step mutation with two undocumented params and an output schema present. The description covers scope, the dry-run protocol, and both parameters, leaving only return-value formatting to the output schema as intended.

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 0%, so the description must carry the load and does: label is the plan code with a concrete example ('HM'), and confirm is the same plan code re-supplied on the second call. This is exactly the semantic the schema lacks, including the otherwise opaque empty-string default.

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 and resource ('take the rest of a plan off the user's Garmin calendar and out of the workout library') and scopes it to future sessions only, which distinguishes it from delete_workout and unschedule_workout in the sibling list. An agent can tell what gets removed without opening the schema.

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?

Specifies the exact call sequence: the first call is a dry run that removes nothing and reports what would go, and a second call with confirm set to the plan code actually removes. It also states the boundary condition (past sessions stay). Nothing about when/how to invoke is left to inference.

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