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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world operation, so the safety profile is covered. The description adds non-obvious behavioral context: that it returns recommendations (best XI, captain) but does not itself grade the squad, and that it can operate from screenshot-derived player names.

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 sentences, each doing a distinct job: usage context, output scope plus exclusion, then required inputs. Usage is front-loaded and there is no filler or restatement of the title.

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 carries the return-value burden and discharges it by naming the expected-points payload, fixtures, best XI and captain. Given two fully documented optional parameters and complete annotations, an agent has everything needed to select and invoke it.

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. The description goes beyond the schema by framing the two parameters as a disjunction ('team ID or FPL link, or player names from a screenshot'), which clarifies that either path is valid and that neither is strictly required, matching the zero-required-parameter schema.

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 a specific resource (an FPL manager's own squad) and spells out exactly what is returned: per-player expected points for the next gameweek with fixtures, plus the best XI and captain. It also carves out its boundary explicitly ('It shows the squad and does not score it'), which separates it from rate_my_team without needing the sibling 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?

It states the intended question types directly: start, bench and captain decisions about one's own squad, and lists the acceptable inputs (team ID, FPL link, or player names from a screenshot). It does not name an alternative tool for the scoring use case, so the when-not is implied by the negative scope rather than routed to a sibling.

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