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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the agent knows it's safe. The description adds value by detailing the output fields (title, description, link, source, publish date, category, country), which aids understanding of what the tool returns.

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 concise: three sentences that front-load the purpose, then detail filtering and output, ending with an example. Every sentence adds value without unnecessary elaboration.

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?

Given no output schema, the description compensates by listing return fields. It covers filtering options and provides an example. It is complete enough for an agent to decide if this tool meets its needs, though a note on pagination or limits could enhance completeness.

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 input schema covers all 4 parameters with descriptions (100% coverage). The description reinforces the meaning by providing examples and clarifying that `coin` accepts comma-separated tickers, which goes beyond the schema's description.

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 'Get the latest cryptocurrency news headlines and articles.' It specifies filtering by keyword, coin ticker(s), and language, and mentions return fields. This distinguishes it from sibling tools like `latest_news`, which is likely general news.

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 suggests usage through examples and mentions filtering capabilities, but does not explicitly compare to alternatives like `latest_news` or `news_sources`. Users can infer when to use it based on crypto focus, but explicit guidance would be beneficial.

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