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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds no behavioral context — no return shape, no pagination, no error behavior, and no note that a default collection is returned when no slug is supplied.

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?

It is short and free of padding, but the two fragments are not front-loaded around the tool's action — the reader learns what a collection is before learning what the tool returns.

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, no annotations beyond the read-only hint, and a vague purpose statement, the description leaves critical gaps: what a returned collection contains and how the default behaves. For a lookup tool this is underspecified.

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 single 'slug' parameter is fully documented with its default, so the schema carries the load. The description's mention of 'selected (Selected characters)' loosely maps to that default value but adds no format or enumeration detail. 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?

The description never states a verb or what the tool actually does — it defines what a 'collection' is ('Hand-picked sets of characters people use most') rather than saying it retrieves one. It is a definitional restatement that does not distinguish get_collection from siblings like get_character or list_blocks.

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?

There is no indication of when to call this tool versus get_character, list_blocks, list_block_characters, or search_characters. The trailing list of collection slugs ('selected') hints at available values but provides no usage context or exclusions.

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