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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's added value is in the extras: results are grouped by game and annotated with rarity, and private cases fail even for the owner. The injection warning about user-authored names and descriptions is genuinely useful behavioral context for an agent that will otherwise echo untrusted strings. It doesn't say what an invalid handle produces, which keeps it off 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 short sentences, front-loaded with the payload description, then the sibling routing, then the safety note. Nothing is redundant with the title or restates the schema, and every sentence adds decision-relevant information.

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 one-parameter read with no output schema, the description covers return content (badges, grouping, rarity), privacy semantics, and untrusted-content handling — enough for an agent to call it correctly. The only gaps are edge behavior such as nonexistent handles or result size, which is a minor omission rather than a blocking one.

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?

There is a single required parameter with 100% schema coverage, and the schema already defines it as 'The member's FloorFeed account name.' The description adds no syntax, case-sensitivity, or lookup-failure behavior beyond the schema. Baseline 3 is correct when the schema carries the parameter definition.

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?

The description states exactly what is returned: 'The badges in a FloorFeed member's public trophy case, grouped by game, with how rare each one is' — resource, aggregation shape, and enrichment are all named. It also implicitly separates itself from verify_trophy_badge and badge_page by scoping the result to one member's public case.

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?

It gives an explicit exclusion plus the alternative: a private trophy case 'isn't readable here, even by its owner: my_trophy_case is.' This resolves the highest-risk sibling confusion. It stops short of routing against other verification/inspection siblings such as verify_trophy_badge or badge_page, so it is clear context rather than a full decision table.

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