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

With no annotations, the description carries the full burden. 'List' implies a read operation and the note about listId hints at the output, but the description does not explicitly disclose read-only behavior, response format, or whether any authorization is needed. Adequate but minimal.

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?

Two short sentences, zero filler. The purpose is stated first, and the usage guidance is front-loaded in the second sentence. Every word earns its place.

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 simple one-parameter list tool, the description is nearly complete: it states what is listed and why the result matters ('needs a listId'). The lack of an output schema means a slightly more explicit return-structure note would be ideal, but the guidance is sufficient in context.

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 the mailbox parameter fully documented including a pointer to list_authorized_mailboxes. The tool description adds no parameter-level detail, but the schema already covers the semantic burden, so the baseline 3 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-resource pair: 'List the user's Google Tasks lists.' It clearly differentiates from sibling tools like list_google_tasks by establishing this tool as the entry point that provides listId values.

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?

'Start here — every other task tool needs a listId' gives clear, actionable context for when to use this tool. It does not explicitly state when not to use it or name alternative tools, but the entry-point guidance is strong enough for an agent to select it correctly.

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