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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds nothing behavioral beyond that: no result ordering, no statement about the default 20-item cap or how to page beyond it, and no note on whether reminders for archived contacts appear.

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?

One sentence, no filler, with the trigger condition front-loaded. The only minor weakness is that the sentence is framed around user intent rather than tool behavior, which costs a little directness.

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 a simple read-only list tool with full annotation coverage, full schema coverage, and an output schema handling return values, the description supplies the needed usage framing. It only omits pagination/ordering notes, which the schema's default limit partly covers.

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 both limit (default 20) and contact_id (optional contact API id) are already documented. The description restates the contact-scoping choice but adds no format, filter, or edge-case detail beyond the schema. Baseline 3 applies when the schema does 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?

Names the resource (reminders) and the two scopes the tool covers: all reminders or those for one contact. An agent can distinguish it from reminders.get, which returns a single reminder. It is phrased as a user-intent trigger rather than a purpose statement, which is slightly indirect but still unambiguous.

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 a usage trigger ("When the user wants to see their reminders") and hints at the all-vs-one-contact split that maps to the optional contact_id. However, it names no alternative (e.g., reminders.get for a specific reminder) and states no when-not condition, leaving the agent to infer routing from the sibling names.

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