scheduled

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 genuinely new behavioral detail beyond them: results are ordered soonest-first and the response includes held-back items along with the reason they were withheld, which tells the agent to expect failure/diagnostic data, not just a clean list.

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 sentence that front-loads the primary output (drafts waiting to be sent) and appends the secondary case (held-back items and why). No filler.

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-value structure need not be described, and annotations carry the safety profile. For a zero-parameter read tool, what it lists and in what order is all the agent needs.

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 zero parameters, so there is no parameter semantics to document; the baseline of 4 applies. The description correctly implies no filtering arguments are available.

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 ('List drafts waiting to be sent by schedule_send'), plus scope details: ordering (soonest first) and inclusion of held-back items with reasons. The reference to schedule_send implicitly separates this read/list tool from the sibling that creates the schedules.

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 description makes the use case clear — inspecting pending scheduled sends and any that failed — but it names no explicit alternative (e.g., draft) and states no conditions under which to prefer another tool. Clear context without exclusions.

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