Purchased PSN library

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

With readOnlyHint=true, the safety profile is already established by annotations. The description adds useful behavioral context beyond that: the inventory includes PS Plus claims, playtime data is only present 'where known', and the tool is meant to surface unplayed purchases. No contradiction with the annotations is present.

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?

The description is two tight sentences with no filler. The first sentence front-loads the data scope, and the second sentence explains when and why to use the tool, earning every word.

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?

The description covers the core use case well and an output schema exists, so return-value details are not needed. However, with five parameters and only 20% schema coverage, the descriptions do not fully explain how to leverage search, platform filtering, or pagination. It also does not contrast with psn_library, which may be a close sibling, leaving some contextual ambiguity.

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 only 20%, so the description needed to compensate for limit, offset, search, and platform, but it does not explain any of those. Only 'unplayed purchases' loosely maps to the unplayed_only parameter. The parameter names are somewhat self-explanatory, which keeps this above a 1.

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 clearly specifies the resource: games the account has bought or claimed, including PS Plus monthly claims, with hours played where known. It also states the practical purpose: avoid recommending owned games and surface unplayed purchases. It stops short of explicitly distinguishing itself from the sibling psn_library, so it is not a full 5.

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?

The description gives an explicit trigger: 'Check this before recommending anything' and explains why, preventing duplicate game suggestions and highlighting unplayed purchases. It does not name sibling alternatives or state when not to use it, but the guidance is clear enough for an agent to know when to call it.

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