List calls and previews

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the useful scope detail that results include both placed calls and pending previews, but says nothing about ordering, result limits, or pagination for what is clearly a list endpoint.

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 fragment with no wasted words and the key scoping terms front-loaded. It is appropriately sized for a no-arg read tool, though it is a noun phrase rather than a full action statement.

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 zero-parameter read tool with annotations covering safety and no output schema, the description is adequate but thin. It omits any hint about result volume, ordering, or how 'recent' is bounded, which an agent selecting among eight siblings would benefit 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline of 4 applies since no parameter semantics are needed.

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?

The description names the resource ('calls' and 'previews') and scopes it ('recent placed', 'pending'), so an agent knows this returns a collection rather than a single call. It does not explicitly contrast with siblings like get_call or place_call, but the plural/recent framing implies a listing operation.

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 statement of when to use this versus get_call or prepare_call, and no preconditions or exclusions. The agent must infer usage purely from the name and the word 'recent'.

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