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

Annotations only say readOnlyHint=false and destructiveHint=false, which is minimal. The description adds meaningful behavioral context: it's free (requires active plan), returns up to 3 items with specific fields, includes price_each_tokens, and clarifies that drawing is a separate paid step. This goes beyond the 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 is compact and information-dense. It front-loads the cost/free status, then the output, then the style parameter, then the sibling relationship. 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?

Given the output schema exists, the description doesn't need to explain return values in detail, but it does summarize them. It covers cost, style options, and the separate drawing step. Minor gap: it doesn't explain what 'hero product' means or how scenario_id is obtained, but the sibling list and output schema fill some context.

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 description coverage is 0%, so the description must compensate. It explains the style parameter by listing the allowed values and noting 'omit to follow the scenario', and it explains scenario_id implicitly as the scenario context. It doesn't detail scenario_id format, but the schema already names it and the description's style guidance adds real value.

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 states the tool finds recurring heroes for a scenario, with a specific verb ('find'), resource ('recurring characters and hero product'), and output details. It distinguishes itself from the sibling tegas_draw_heroes by noting drawing is a separate paid step.

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 provides clear context: it's free but requires an active plan, and it explicitly says drawing is a separate step via tegas_draw_heroes. It doesn't explicitly state when not to use it, but the alternative is named and the relationship is clear.

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