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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds real behavioral context beyond them: each call returns up to 20 article previews and paging must advance start_index in increments of 20. It does not cover edge behavior such as end-of-feed signaling, but with an output schema present that is a minor gap.

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 tight sentences. The primary scope is front-loaded and the routing alternatives follow immediately, with zero 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 single-optional-parameter read tool with an output schema and readOnly/openWorld annotations, the description supplies everything an agent needs: scope, page size, and the sibling-routing decision. Nothing material is missing.

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 baseline is 3, but the description goes further by disclosing that each offset yields up to 20 previews and that start_index must be stepped in increments of 20. That is pagination semantics the schema's 'zero-based offset' wording does not supply.

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 verb (Fetch) and a precisely scoped resource (FotMob's global English latest-news feed), then names the three sibling feeds it is not. An agent can distinguish this from fotmob_news, fotmob_team_news, and fotmob_trending_news without opening any schema.

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?

Explicitly routes the agent: use fotmob_news for a league, fotmob_team_news for one team, fotmob_trending_news for the curated Trending shelf. The selection condition for each alternative is stated, leaving nothing to inference.

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