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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds useful return-field context (language, country, kind, health) but says nothing about pagination, result caps, or how health is computed. With annotations carrying the behavioral burden, this is a reasonable if modest contribution.

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?

Two short sentences, zero filler, with the resource and its returned fields front-loaded ahead of the filtering clause. Nothing could be removed without losing information.

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, no-required-parameter list tool with no output schema, the description covers what is returned and how to filter, which is most of what an agent needs. The remaining gap is parameter format specifics (lang/country code conventions), which is minor at this complexity level.

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?

Schema description coverage is 0%, so the description is the only source of parameter meaning. It correctly identifies all three parameters and clarifies that q matches by name, but gives no format guidance for lang or country (ISO codes? free text?). It partially compensates for the coverage gap without fully closing it.

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 resource (registered sources) and enumerates the attributes returned (language, country, kind, health), so it is clearly distinguishable from list_stories and the other news-oriented siblings. It is not a tautology of the title. It stops short of an explicit verb+scope statement like 'lists all sources without pagination', but the intent is unmistakable.

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?

'Filter by q (name), country or lang' implies how to narrow results, which is implicit usage guidance. There is no statement of when to reach for this tool versus find_entities or search_news, and no exclusions or prerequisites. Adequate but leaves routing to inference.

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