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

Annotations already declare readOnly/destructive/openWorld, so the safety profile is covered. The description adds value beyond them: the default scoping to open activities only, and the auth requirement ('Needs the user's Cotlet API key with access to this app'), which an agent needs before calling.

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 and reasonably sized, but it repeats the return field list twice ('to-dos for a user and date, with type, contact and due date' then 'type, contact, reference and due date'). That duplication dilutes an otherwise tight paragraph.

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?

No output schema exists, but the description enumerates the returned fields and states the auth prerequisite and default filtering, which is enough for an agent to call it correctly. Slightly more detail on pagination or result limits would round it out.

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%, so all four parameters are already documented in the schema. The description restates include_completed behavior and the date/assigned_to defaults but adds no syntax or format detail beyond what the schema provides; baseline 3 applies.

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 ('List activities' / 'Returns the Activity List') and pins down the scope ('for one user and day'). It distinguishes itself from one sibling by referencing complete_activity, though it does not differentiate from other list tools like list_appointments.

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 concrete conditional guidance ('Open activities only, unless include_completed is set') and an explicit companion call pattern ('Use activity_id with complete_activity'). It lacks exclusion guidance against other MarketSharp list tools, so it is not a full 5.

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