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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that collections are tied to a device browse page, implying a device/platform dependency, but says nothing about pagination, result volume, or auth. Modest added context over the annotations, so a 3.

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 sentences, action first, chaining instruction second, with zero filler. The discovery step is front-loaded ahead of the downstream call.

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 an output schema present, return values need not be explained, and annotations carry the safety profile. The description supplies the discovery-and-chain workflow, leaving only minor gaps such as result scope or pagination that are not essential to invoking it 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 Platform, Country, and Lang are already documented, and the platform enum values live in the schema. The description only reinforces that the same platform must be reused for the follow-up call, which is marginal added meaning. Baseline 3 is correct.

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 (Discover) and resource (Apple App Store room and EDS collections) with the qualifying scope 'linked from a device browse page', which an agent can act on. It also implicitly distinguishes itself from appstore_collection by positioning this tool as the ID-discovery step. The 'room and EDS' terminology is internal jargon that slightly blurs what the user actually gets.

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 names the follow-on tool and the condition for using it: 'Use the returned collection ID with appstore_collection and the same platform to retrieve its apps.' This gives a clear workflow context. It lacks any when-not-to-use or alternate-path guidance, so it stops 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.