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

Annotations already declare readOnlyHint=true and openWorldHint=true, and an output schema documents the return shape, so the burden on the description is limited. It does add one genuine behavioral detail beyond the structured fields: 'creator account codes are omitted,' telling the agent that some valid-looking codes yield nothing. It says nothing about error behavior for malformed or unknown codes, which is the main remaining 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 short sentences, front-loaded with the core purpose, with the input sourcing and the exclusion following in order of importance. No filler or restated boilerplate.

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-parameter, read-only lookup with a full schema, full parameter coverage, annotations, and an output schema, the description covers purpose, input sourcing, and the main exclusion. It stops short of describing failure modes or whether all public islands carry tags, which keeps it from being fully complete.

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 the single parameter is fully documented in the schema, making 3 the baseline. The description adds modest meaning by naming accepted input forms and excluding creator account codes, but introduces 'playlist name' as a third term not used in the schema, which adds mild ambiguity rather than clarity.

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 and resource: 'Returns public metadata and tags for one island code or first-party display name.' That clearly separates it from the list-style fortnite_islands, but it doesn't distinguish itself from the metric siblings (fortnite_island_metric/fortnite_island_metrics), which an agent could plausibly confuse with a metadata lookup.

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 says to source the input 'from fortnite_islands or a playlist name', giving an actionable path to obtain a valid code. It does not state when an agent should prefer fortnite_island_metric or the rankings tools instead, so exclusions are absent even though context is clear.

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