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

Annotations declare a non-read-only, open-world call, and the description adds meaningful operational detail on top: the exact return fields and the instruction to persist editToken as a credential for later add_item calls. It omits auth requirements, rate limits, and whether repeated calls create duplicates.

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 short sentences, all front-loaded with purpose first, then return values, then the sibling handoff. Nothing is padded and no sentence is filler.

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 adequately covers output shape (important since no output schema exists) and credential handling for a mutating, open-world tool. But for a 7-parameter create call with 29% schema coverage, it leaves the agent guessing about the content parameters and about marketplace's real required status.

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 29% (locale and marketplace only), so the description needs to carry the burden and does not — items, genres, platforms, budgetBand, and gamerName get no explanation anywhere. Worse, marketplace is documented as "REQUIRED" in the schema while the required list is empty, and the description never resolves that ambiguity.

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 ("Create a gaming wishlist") and enumerates what comes back, so the agent knows exactly what the call produces. It also distinguishes itself from sibling create_and_fill by naming that one as the preferred one-shot path.

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?

"Preferred one-shot: create_and_fill" gives an explicit routing rule, and "Save editToken for add_item" tells the agent the follow-up path. It stops short of stating the condition under which this tool beats create_and_fill, or when not to use it at all.

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