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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds a genuine behavioral constraint not in the annotations ("App-only"), but says nothing about return format, latency, or how news/fixtures data behaves when absent.

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, with the availability constraint front-loaded before the content list. The single long clause enumerating breakdown sources is dense but every item is informative, so nothing is wasted.

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 correctly compensates by enumerating the returned data (points by gameweek and by source, fixtures, news). For a one-parameter, read-only tool this is nearly sufficient; the only real hole is the lack of differentiation from similarly named siblings.

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 100%, so player_id's meaning and 1-5000 range are already fully documented in the schema. The description adds no parameter-level detail (e.g., where to obtain the element id), which is acceptable given the schema does the work.

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 names the resource (a player's card) and enumerates the content returned: expected points by gameweek and by source, fixtures, and news. It is clear what the tool produces, but it never distinguishes itself from the sibling get_player or the near-identically named get_player_breakdowns, so an agent could easily pick the wrong one.

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?

It supplies a trigger context ("calls this when the user taps a player") and an availability constraint ("App-only"), which implies when it applies. However, it gives no explicit when-to-use vs when-not-to-use guidance against get_player, get_player_breakdowns, or any other sibling, leaving routing to inference.

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