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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds the sort order (soonest first) and the due-filter meaning, but says nothing about pagination, result size, or whether reminders from all threads are included.

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 compact sentence with the resource and ordering front-loaded and the parameter hint folded in economically. Every clause earns its place.

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 with one optional boolean, one annotation pair, and no output schema, the description covers purpose, ordering, and the filter's intent. Minor gaps remain on default due_only behavior and result volume.

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 0% for the single due_only boolean, so the description must carry the meaning. 'due_only for the ones that have come round' conveys that true restricts to currently-due reminders, but the wording is colloquial and leaves the false/default behavior unstated.

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 resource ('pending follow-up reminders on email threads') and behavior ('soonest first'), which scopes it away from sibling listing tools such as overdue_tasks or quotes_to_follow_up. It stops short of naming a sibling or explicitly contrasting scope, so a 4 rather than 5.

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 parenthetical hints at when to set due_only (when you only want items that have come round), which is implicit usage guidance. There is no explicit when-to-use-vs-alternatives statement directing the agent away from overdue_tasks or search_inbox.

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