List VR.org news sources

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

Annotations already establish readOnly=true, destructive=false and openWorld=true, so the safety profile is covered. The description adds real behavioral value by disclosing what is returned (per-source article counts, status, aggregate totals), which matters because there is no output schema.

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 with no filler, front-loading the resource and immediately enumerating the returned fields. 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?

With no output schema, the description carries the burden of describing the return shape, and it does so adequately (counts, status, totals). Minor gaps remain — 'status' is undefined and no ordering or pagination behavior is mentioned — but nothing essential is missing for a no-arg catalogue lister.

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 there is nothing for the description to disambiguate; baseline for zero-param tools is 4. No filter or pagination options exist that would need explaining.

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 pairs a specific verb ('Returns') with a specific resource ('the news sources VR.org aggregates') and even previews the payload (per-source counts, status, totals). It is clearly distinct from siblings like search_vr_news or get_vr_article, though it does not explicitly name those alternatives as a contrast.

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 explicit when-to-use or when-not-to-use guidance, and no sibling is named as an alternative. However, for a zero-parameter list tool that enumerates the source catalogue, the intended use is strongly implied by the resource itself.

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