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

No annotations are provided, so the description carries the burden. It discloses that the tool returns information about templates (good for and width in pixels), but it doesn't mention return format or any side effects. Since it's a listing operation, it's likely safe, but the description doesn't explicitly state that it is read-only or non-destructive. It adds some value beyond the annotations (which are absent) but not a full behavioral profile.

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 front-loads the key info: these are layouts for create_email_signature. It is efficient and doesn't waste words. It could be structured slightly better by starting with 'Lists' but it's still clear and brief.

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 no output schema and no annotations, the description needs to explain what the tool returns. It does mention the content (layouts, good for, width), but it doesn't specify if the return will be a list of objects, IDs, or how to reference them. Since it's a simple listing tool with no params, this is acceptable but not fully complete. The description gives enough for an agent to know its purpose, but the return format is missing.

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?

There are no parameters, so the description doesn't need to explain parameters. The baseline for 0 params is 4, and the description adequately explains what the output will contain (layouts, what each is good for, width in pixels), which is useful for the agent to interpret the return value. It doesn't describe the return structure, but with no parameters it's fine.

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 states the tool lists signature templates and what they are good for, with width in pixels. It references a specific use case 'pass to create_email_signature' which gives context, but it doesn't explicitly define the purpose as 'list available templates' in a standalone way. It is clear but could be more specific about the action of listing.

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 usage: to know what to pass to create_email_signature. It doesn't mention when not to use it or alternatives, but since there are no sibling tools that do something similar, the implication is adequate. It could be improved by stating that this is the direct source for template IDs, but it is not misleading.

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