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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds real value beyond them: it discloses what is deliberately withheld (no personal name, email or ID) and defines partial-failure semantics — teamName is null when FPL is unreachable while tier and teamLinked remain accurate. That degradation contract is exactly the kind of context an agent cannot get from structured fields.

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?

Front-loaded with the verb and resource, and the field list comes before the usage hint and the null-handling caveat, which is the right priority order. It is dense — three distinct facts compressed into two sentences — but nothing is redundant.

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?

There is no output schema, so the description carries the return-value burden, and it names all three returned fields plus their null behaviour. For a zero-parameter read tool with annotations already covering safety, nothing an agent needs in order to call it or interpret the result 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?

The tool takes no parameters, so there is no parameter meaning to add and the baseline of 4 applies. The description correctly spends no words on inputs.

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 ("Check") and resource ("the authenticated FPLai account") and enumerates exactly what is reported: tier, whether an FPL team is linked, and teamName. That field list distinguishes it cleanly from every sibling, which are all analysis, player, fixture or squad tools.

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 a concrete use case with a rendering example ("use it to confirm which team is connected, e.g. 'connected as <teamName>'"), so an agent knows when to reach for it. It stops short of naming alternatives or stating when not to use it, so it falls short of a 5.

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