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

Annotations already declare write operation (readOnlyHint false), non-destructive, and non-open-world. The description adds useful behavioral context beyond annotations: it creates a multi-tab spreadsheet, supports optional title, prescribes headers in row 1 when populating, and tells where the sheet appears.

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 front-loaded sentences with zero waste: what it creates, how to populate it, and what to tell the user. Every sentence contributes actionable guidance.

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 creation tool with no output schema, the description covers the core action, next step, and outcome location. It omits workspace/auth nuance that the schema documents, but no critical calling information 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 description coverage is 50%; the workspace parameter is documented in the schema, but title has no schema description. The description only says 'optionally titled,' adding minimal semantic detail and no format or length guidance, so it does not fully compensate for the coverage gap.

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 ('Creates') and resource ('Napkin sheet'), clarifies it is a multi-tab spreadsheet, and explicitly names the sibling tool for populating it (napkin_sheets_set_cells). This clearly distinguishes it from update/list/query siblings.

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?

Gives clear context for use: create the sheet, then populate via napkin_sheets_set_cells, and tell the user where it landed. It does not explicitly state when not to use it or name alternative creation/update tools, but the intended workflow is unambiguous.

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