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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds one genuinely new behavioral detail — that sent, cancelled and failed entries are included in the results — but says nothing about ordering, volume, or how sent items remain in a 'scheduled' listing.

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?

A single short sentence with the resource and scope front-loaded and no filler. The phrasing is slightly telegraphic (no verb), but nothing is wasted.

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 zero-parameter, closed-world read with rich annotations, little explanation is required, and the status enumeration is a helpful addition. However, with no output schema there is no statement of return shape, ordering, or volume, which is the one thing an agent would still want before calling 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?

The tool takes no parameters, so the schema carries no semantics for the description to supplement. Baseline of 4 applies; the description appropriately avoids inventing parameter behavior.

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 specific resource (scheduled messages) and scopes it to the workspace, and it discloses which statuses appear in the result (sent, cancelled, failed) — information an agent cannot infer from the name alone. It stops short of differentiating itself from siblings like list_scheduled_posts or list_messages, and it is a noun phrase rather than an explicit verb+resource statement.

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?

There is no when-to-use guidance, no mention of alternatives such as list_scheduled_posts, and no conditions under which this tool is the wrong choice. The agent must infer the selection rules from the tool name alone.

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