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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds useful behavioral context beyond that: the return is full JSON configuration and includes fields the list view lacks (cron, skip dates, channel toggles, voice override). It does not contradict any annotation.

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 purpose in the first sentence, then usage, then the argument note. Everything earns its place, though the field enumeration ('spoken message, cron expression, skip dates...') in the usage sentence slightly runs 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?

An output schema exists, so return values need not be explained. For a one-parameter read tool with strong annotations, the description supplies everything an agent needs: purpose, when to use, an alternative to avoid, and where the ID comes from.

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 parameter. It does add provenance ('Reminder ID from list_reminders'), telling the agent where to obtain a valid ID, which is real value the schema lacks. It stops short of format details, but for a single opaque ID that is acceptable.

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 ('get the full configuration of one reminder') and immediately distinguishes it from the sibling list_reminders by noting it returns detail the list omits. An agent can tell it apart from list_reminders and update_reminder without opening a 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?

Explicit when-to-use: 'when you need detail that list_reminders omits — the exact spoken message, cron expression, skip dates, channel toggles, or voice override.' It also names a second scenario (read before a partial update to avoid overwriting settings), which is concrete and actionable.

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