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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), but the description adds a genuinely non-structured behavioral fact: a per-record credit cost with a minimum of 2, which directly affects how the agent should call it. It stops short of describing anything else about the response or rate behavior, hence a 4 rather than 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, each earning its place: what the resource is, what it costs, and which siblings to use instead. The resource definition is front-loaded and no sentence is redundant.

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 read-only search tool with an output schema, the description covers everything needed to choose and invoke it: the resource, the cost model affecting pagination, and the disambiguation from siblings. Return values are already handled by the output schema.

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%, so the baseline is 3, and the description goes beyond it by tying page_size to the credit cost ('keep page_size to what you need'), which the schema does not convey. It does not add meaning for date, app_id, sort, or page, but those are fully documented in the schema.

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 (search) and a precise resource (stored daily concurrent-player time-series records, one per tracked game and date). It also names the two closest siblings it must not be confused with, so an agent can identify it without opening any 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?

Explicitly routes the agent: steam_players for live counts, datasets_steam_charts_search for stored chart snapshots, leaving this tool for stored daily player-count time-series. The alternatives and the condition that selects them are stated outright rather than implied.

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