List Seedream image sizes

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered without the description. The description's only behavioral addition is the 'Returns: Formatted list...' line, which largely duplicates the existing output schema. Adequate but not additive.

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?

Front-loaded with the purpose, which is good, but the three 'Use this when' bullets are near-synonyms of one another and the 'Returns' section restates the output schema. Roughly a third of the text could be cut without loss of signal.

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-parameter, read-only listing tool with a full output schema and complete annotations, the description covers purpose, timing, and return shape. Nothing essential is missing, though it adds little that the structured fields do not already supply.

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 tool takes zero parameters, so there is no parameter semantics to document; baseline is 4. The empty schema is self-explanatory and the description correctly does not invent arguments.

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: 'List all available image sizes and resolution options for Seedream.' This is unmistakably distinct from siblings like seedream_generate_image or seedream_get_task. It stops short of naming seedream_list_models as the nearest-lookalike sibling, so an agent must infer the split between 'sizes' and 'models'.

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 'Use this when:' block gives three concrete invocation conditions (user asks about sizes, agent needs to choose resolution, agent wants to understand options). That is real when-to-use guidance, but there are no exclusions or named alternatives, so it falls short of a 5.

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