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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so safety behavior is established. The description adds useful behavioral context beyond annotations by noting that results show profession coverability and hero unlock methods, which informs the agent about the nature of the returned information.

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 two sentences with no filler. It front-loads the core action and filters, then adds a concise purpose statement. Every sentence contributes useful 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?

With full parameter documentation, a rich output schema, and annotations covering the read-only/idempotent behavior, the description covers what the tool does and why it is useful. Nothing critical is missing for correct invocation.

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 100%, with both parameters fully documented and exact allowed values listed. The description only restates that optional filtering by profession or campaign is available, adding no significant semantic detail beyond the schema.

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 opens with a specific verb and resource: 'List all GW1 heroes', which clearly identifies the tool's function. It also differentiates from siblings like get_hero (single hero retrieval) and skill-focused tools by emphasizing hero listing with optional filters.

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 states the tool is useful for team-building and explains that it reveals profession coverage and hero unlock status, which implies an appropriate use case. It does not explicitly name alternatives or exclusion conditions, but the context is clear enough for an agent to decide when this listing tool is relevant.

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