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

Annotations already declare this is a safe, closed read (readOnlyHint, non-destructive, openWorldHint=false), so the bar is lower. The description adds genuinely useful context beyond that: the specific return fields (community trade value, demand, catalogue rank, listing frequency, collection date) and the important caveat that values are community estimates rather than official Roblox prices.

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?

Front-loads the core purpose, then layers in return fields, a usage example, and a caveat in three tight sentences with no filler. Slightly dense, but every sentence earns its place.

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 no output schema, the description carries the burden of explaining what comes back, and it does so explicitly (value, demand, catalogue position, listing frequency, collection date) while also flagging the estimate caveat. An agent has everything needed to call and interpret this tool.

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% and the enum already documents the three game values, so the schema does the heavy lifting. The description restates the game list but adds no new syntax or format guidance for the parameters beyond what is already structured, making the baseline 3 appropriate.

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 ('what one item is worth') and names the three supported game catalogues (FTF, MM2, Adopt Me), which cleanly separates it from siblings like list_values or check_trade. An agent can tell instantly that this is a single-item valuation lookup.

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?

Gives a concrete usage trigger with the worked example question ('how much is a Chroma Luger worth in MM2'), so the agent knows what kind of query maps here. It does not, however, mention when to prefer a sibling such as list_values or check_trade, so routing between related tools is left to inference.

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