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

Annotations already declare readOnlyHint and idempotentHint. The description adds valuable context beyond this: it explains that IDs in the breakdown are stable, cross-referenceable with riddle_get's build configuration, and not a display order—with non‑contiguous numbers being expected. This informs the agent about how to interpret data and avoid treating gaps as errors, which is behavioral nuance not in annotations.

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?

The description opens with the essential purpose in one clear sentence, then adds a two-sentence note about ID stability and cross-referencing. The ID explanation is verbose but essential to avoid misinterpretation, and the structure front-loads the main purpose. It is appropriately sized for the tool's complexity.

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?

Given the moderate complexity (3 params, no output schema), the description provides a clear picture of what the tool returns and clarifies a critical behavioral nuance (ID semantics). It does not detail the exact structure of the response, but the description gives enough context for an agent to infer how to use the data, and the schema covers inputs. The description is well-aligned with available structured information.

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?

The schema documents all three parameters (riddleUUID, dateFrom, dateTo) with full descriptions and formats, so schema coverage is 100%. The description does not add additional meanings to the parameters—it only references the output's ID semantics, not the input parameters. Since schema already covers everything, a baseline of 3 is 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?

The description clearly identifies the tool as 'Returning a detailed stats breakdown for a specific Riddle' and lists examples of returned data (titles, choices, views, time spent, submissions). The verb 'returns' and the resource 'stats breakdown for a specific Riddle' set it apart from sibling tools like stats_project_breakdown (project-level) and stats_user_breakdown (user-level).

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?

The description implies this tool is for getting stats targeted to a single Riddle (via riddleUUID), but it does not explicitly state when to use this over sibling stats tools or mention alternatives. There is no 'when-not-to-use' or 'consider X instead' guidance, making usage context inferred rather than explicit.

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