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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuine behavioral context beyond that: 'Nothing is stored' (no server-side persistence) and the exact contents/alerts baked into the .ics, which the annotations do not convey.

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 tight sentences, front-loaded with purpose and output contents before the sibling routing note. Every clause earns its place with no 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?

There is no output schema, yet the description fully documents the return artifact (all-day .ics event with steps, official link, and 9am alerts on the day before and day of). Combined with the 'Nothing is stored' note, an agent has everything needed to call and interpret it.

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 100% and each parameter is already well documented in the schema. The description adds only indirect meaning, hinting that renews_on drives the computed cancel-by day and that service behaves 'as for get_cancel_steps'. Baseline 3 is appropriate when the schema carries the parameter burden.

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 (generate a calendar reminder/.ics for the cancel-by day) rather than restating the name. It also implicitly distinguishes itself from the sibling get_cancel_steps by describing a different artifact (a downloadable calendar file versus steps).

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 final sentence routes the agent: get_cancel_steps surfaces this link as add_to_calendar whenever renews_on is given and the day hasn't passed. That is clear contextual guidance tied to a sibling, though it never states an explicit when-not-to-use condition (e.g. what to do once the day has passed).

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