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 value beyond that: market values are included by default, and the profile carries player-specific season IDs that feed other tools. It does not discuss rate limits or response size, so it stops short of a 5.

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?

Three tight sentences: payload first, then id discovery, then alternative tools. Nothing is redundant and the most important constraint (id source) is front-loaded after the payload statement.

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?

An output schema exists, so return values need no explanation, yet the description still summarizes them for selection purposes. Combined with the id sourcing and sibling routing, an agent has everything needed to choose and call the tool correctly.

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 both parameters (id, include_market_values) are already documented in the schema. The description reinforces the id's provenance and the market-value default, but adds no syntax or format detail beyond the structured fields, so the baseline 3 applies.

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?

Specific verb ('Fetch') plus resource ('public FotMob player profile') with an explicit enumeration of the payload: current team, injuries, recent matches, career history, trophies, market values, season IDs. This is clearly distinguishable from siblings like fotmob_player_stats and fotmob_player_matches, which the description itself calls out.

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?

Gives both the prerequisite ('Discover the player `id` with fotmob_search') and the alternatives with the condition that selects them ('Use fotmob_player_stats or fotmob_player_matches for deeper history'). An agent knows exactly when to route elsewhere.

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