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

Annotations already disclose a non-destructive write (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the safety profile is covered. The description adds modest behavioral context ('optionally titled', 'Tell the user where it landed', the Sheets tab location) but says nothing about permissions/auth requirements or what the operation returns, which is the bulk of the remaining burden.

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?

Three tight sentences, front-loaded with the purpose, then the next-step workflow, then the UX instruction. Each sentence earns its place with minimal waste.

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?

There is no output schema, yet the description does not say what the call returns (e.g., a sheet reference/ID needed by set_cells), which the agent needs to chain the follow-up call. It covers the workflow and UX hint well but leaves the return value implicit, so it is adequate rather than complete.

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 50%: 'workspace' is fully documented in the schema (including token/API-key rules), while 'title' has no schema description. The description's 'optionally titled' compensates partially by signaling title is an optional label, but adds no format or constraint detail beyond that. Baseline 3 is appropriate given the schema carries half the load.

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 gives a precise verb+resource ('Creates a Napkin sheet') and usefully clarifies that a sheet is a 'multi-tab spreadsheet', preventing confusion with a single-tab concept. It is distinguishable from siblings like napkin_sheets_list/query/update by the create semantics, though the description never explicitly contrasts them, so the differentiation leans on the tool name.

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?

It gives a clear follow-up workflow: 'Then populate it with napkin_sheets_set_cells (headers in row 1)', naming the alternative tool to use next and the convention for row 1. It provides clear context for the create-then-populate sequence, but stops short of explicit when-not-to-use or exclusion guidance.

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