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

The tool is annotated with readOnlyHint: true, and the description says 'List', which is consistent. However, the description adds no behavioral details beyond that, such as response format, ordering, pagination, or any side effects. With annotations already covering the read-only nature, the description contributes no incremental transparency.

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 a single, concise sentence that conveys the essential action and target. There is no redundancy or irrelevant information, making it highly efficient and well-structured for quick parsing.

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?

The tool is a simple read-only list operation with one input parameter and no output schema. The description covers the core functionality but omits context such as what fields are returned, whether the list is ordered, or if any filtering applies. Given the minimal complexity, it is adequate but not fully comprehensive.

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 has a single parameter 'project_id' with a brief description 'Project id.' The tool description does not elaborate on this parameter (e.g., format, constraints, or how it identifies the project). Since schema coverage is 100% for the parameter, the baseline is 3, and the description adds no extra meaning.

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 action ('List') and the resource ('a project's characters'), which is unambiguous. It does not explicitly contrast with the sibling tool 'get_character' (which likely retrieves a single character), but the plural 'characters' and the project context imply a list operation, making the purpose clear.

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 no guidance on when to use this tool versus alternatives. It does not mention situations where listing all characters is preferred over retrieving a single character or using other list tools, nor does it exclude any use cases. This leaves the agent to infer usage from the name alone.

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