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

Annotations already cover read-only/idempotent/destructive safety, so the description adds genuinely new behavior: no paging, and the important partial-failure contract that an unreadable account is reported under 'Not listed' rather than failing the call. That failure-mode disclosure is non-obvious and valuable.

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 verb+resource, then scope, then return fields, then the failure contract, then the alternative. Three tight sentences, no filler, every clause carries information.

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?

No output schema exists, and the description compensates by enumerating returned fields and the partial-failure behavior. For a single-parameter read-only list tool, nothing an agent needs to invoke it correctly 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?

Schema coverage is 100% and already documents the email parameter with its 'Default: every account' semantics. The description restates that scope but adds no syntax or format detail beyond the schema, 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?

States a specific verb and resource ('List notebooks') plus the exact fields returned (id, title, emoji, source count, timestamps), and explicitly distinguishes itself from notebook_get_notebook. An agent can tell it apart from siblings like notebook_list_accounts or notebook_get_notebook without opening a schema.

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?

Clearly frames scope ('one account or every account of this API token') and routes the agent to notebook_get_notebook for a single notebook's sources and artifacts. It lacks explicit when-not guidance relative to other list tools, but the alternative routing is concrete.

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