list_sources

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

Annotations already declare readOnly, idempotent, non-destructive. The description adds the behavioral trait that this operates 'without network access', which is not covered by annotations and is meaningful for an agent deciding to call it in an offline environment. It also hints that only 'discoverable' sources are included, adding nuance about the result scope.

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?

The description is a single sentence, front-loaded with the verb 'List', and every word earns its place. It conveys the action, resource, scope qualifier, and a key operational constraint without any 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?

For a simple list operation with no parameters, an output schema present, and strong annotations, the description is complete. It provides the essential operational context (offline, discoverable sources) without needing to explain return values or error behavior, which the output schema would cover. The complexity is low, so the description fully satisfies what an 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?

This tool has zero parameters, so the schema is empty and description coverage is trivially 100%. Per the scoring guide, a 0-parameter tool scores a baseline of 4 because no parameter explanation is needed. The description doesn't need to add anything, and it doesn't.

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 clearly states the action ('List') and the resource ('all discoverable WhatsHot sources'), with a specific qualifier 'without network access' that adds meaning beyond a generic list operation. It distinguishes from siblings like fetch_current or get_source_schema, which target different actions.

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 implies when to use this tool: when you need to enumerate all discoverable sources, particularly in an offline context ('without network access'). While it doesn't explicitly name alternatives, the sibling tools clearly serve different purposes, so the usage context is evident. The lack of an explicit 'use instead of X' prevents a 5.

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