list_lists

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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering safety and non-exhaustiveness. The description adds scope details about including default lists and flagged emails, which is helpful, but it does not disclose return format, ordering, or whether results include IDs needed for later mutations.

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?

One sentence with no filler. It leads with the core action ('List all To Do lists') and adds the important default-list detail in a parenthetical, making it front-loaded and concise.

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 no-argument read-only tool, the description is nearly complete. It states what is listed and even enumerates the default entries; the only minor gap is that without an output schema it does not say what fields each list object includes, but that is not necessary just to invoke the tool.

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 has zero parameters and the schema is trivially complete. With no parameters to document, the description has little semantic burden, so the baseline 4 applies.

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 uses a specific verb and resource: 'List all To Do lists', and it clarifies the scope by calling out the default 'Tasks' list and 'Flagged Emails'. This clearly distinguishes it from sibling tools like create_list, rename_list, delete_list, and list_tasks.

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 tool's purpose is obvious and the 'all' wording implies it is the enumerating read operation for To Do lists, but it does not explicitly state when to prefer it over siblings such as list_tasks or when it should be used before rename/delete operations. Usage context is implied rather than explicit.

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