News Sources

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

Annotations already declare readOnlyHint and idempotentHint, so the tool is known safe. The description adds behavioral clarity by specifying filtering options and showing example filter combinations, which helps the agent anticipate results. It doesn't mention rate limits or pagination, but these are less critical given the read-only nature.

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 well-organized with a summary, a bulleted Args list, and examples. It is concise and all information serves a purpose, with no redundancy.

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?

The tool is simple and read-only, with all parameters documented and examples provided. No output schema exists, but the description implies the return is a list of sources. It could be more explicit about response format, but given the simplicity, it's adequate.

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 coverage is 100%, so the baseline is 3. The description adds value with concrete examples (e.g., language='en', category='technology') and clarifies prioritydomain values, making parameter usage more actionable.

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 'List available news sources with filtering options' and explains 'Browse and discover news sources indexed by NewsData.io'. This specifies the verb (list) and resource (sources), distinguishing it from sibling tools that handle news articles.

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 provides context through examples like 'English tech sources' and 'US news sources', implying when to use the tool for source discovery. It doesn't explicitly exclude other tools but clearly scopes the use case to source listings rather than news content.

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