add_sheet

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

No annotations are provided, so the description carries the full burden. It does disclose a real precondition ('must not already exist' for the title), which is useful behavioral context, but it says nothing about required permissions, whether the operation modifies existing tabs, or side effects of a mutation on a live spreadsheet.

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?

The core purpose sentence is front-loaded and concise, and the Args block is compact. The structure is slightly padded by the Python-style Args formatting, but no sentence is wasted.

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?

An output schema exists, so return values needn't be explained, and both parameters are documented. However, for a mutation tool with zero annotation coverage, the lack of permission requirements or effect disclosure leaves a meaningful gap.

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 0%, so the description must compensate, and it does: it explains spreadsheet_id as 'the long token from the spreadsheet URL' and title as the new tab name with a uniqueness constraint. Both parameters gain meaning beyond the bare schema types.

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 ('Add a new tab to an existing spreadsheet'), which cleanly separates it from create_spreadsheet (creates the whole spreadsheet) and the read/write range tools. It stops short of explicitly naming the sibling it contrasts with, but the resource scope is unambiguous.

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 phrase 'existing spreadsheet' implies the prerequisite that the target spreadsheet must already exist, but there is no explicit when-to-use vs create_spreadsheet guidance or list of exclusions. Usage is only implied.

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