List saved characters

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

Annotations already establish readOnlyHint=true, so the safety profile is covered; the description contributes the ordering guarantee ('newest first') and the conditional payload ('variant group and tournament verdict when present'), which are genuine behavioral facts beyond the annotations. However, it is silent on pagination, result caps, and what happens with large collections — significant gaps for a list tool.

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?

One compact sentence, front-loaded with the action and resource, followed by ordering and payload details in a parenthetical. No redundant or hedged wording, though the parenthetical packs two distinct facts that could be separated for skimming.

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 zero-required-parameter read-only list tool with no output schema, the description covers ordering and the most notable returned fields, which is close to sufficient. It still omits whether results are paginated or capped, so an agent cannot predict volume or whether a follow-up call is needed.

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 optional parameter with 100% schema description coverage, so the schema already explains that 'group' restricts to variants of that group. The description only echoes the concept via 'variant group' and adds no filtering semantics or format detail beyond the schema, making the baseline of 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 ('Lists saved characters') and adds the defining scope detail that only saved characters are returned, contrasting implicitly with save/create/get siblings. It also discloses sort order and enriched fields, so an agent can tell what it returns without opening anything else.

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?

Use is only implied: the agent can infer this is the enumeration path versus character_get, but the description never says when to call it or when to prefer an alternative. It does surface the 'variant group' filter as a routing condition, which is partial guidance rather than explicit when/when-not rules.

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