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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint=false), so the burden is lighter. The description still adds real behavioral value by defining "real price" as list price plus checkout fees and disclosing the ranking order, which no structured field carries. It omits pagination or result-size limits, keeping it short of a 5.

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, zero filler: trigger queries first, then payload/ordering, then the redirect to the alternative. Front-loading the usage triggers ahead of implementation details is exactly the right ordering for an agent scanning for a match.

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?

There is no output schema, and the description compensates by enumerating the returned fields and their ordering. Combined with 100% parameter coverage and annotations covering safety, nothing an agent needs to call this correctly is missing.

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 100% with four well-documented parameters including defaults, so the schema does the heavy lifting. The description mentions comparing across stores (Steam, GOG, Epic), which loosely maps to include_marketplaces, but adds no syntax, format, or fallback detail beyond the schema. Baseline 3 applies.

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 all current offers) plus the exact payload fields (real price, edition, platform, notes) and the ordering rule. It explicitly contrasts itself with get_cheapest_way_to_play, so an agent can route between the two without opening either 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?

Opens with literal user queries this tool answers ("Show me every store price for <game>", "Compare prices..."), which is an unambiguous trigger. It then names the alternative (get_cheapest_way_to_play) and the condition that selects it (single recommendation).

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