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

Annotations already declare the non-read-only, non-destructive, non-idempotent profile, and the description adds genuinely new behavioral context: an edit-permission requirement, a uniqueness validation constraint on the new name, and that the change is 'Applied through the collaboration server' (implying propagation to other users). It does not say what happens on a name collision or whether formulas referencing the old sheet name are updated.

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?

Four short sentences, front-loaded with purpose and followed by the key constraints. The trailing signature line is redundant with the input schema and is the only sentence that does not earn 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?

An output schema exists, so return values need no explanation, and the description covers permissions, the uniqueness constraint, and the collaboration-server channel. Remaining gaps — conflict-error behavior and impact on formulas or references to the old sheet name — are modest for a three-parameter rename tool.

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 67%: 'sheet' and 'new_name' are documented in the schema, but 'file_uuid' has no description anywhere. The 'Signature: sheets_rename(file_uuid, sheet, new_name)' line merely restates parameter names and adds no semantics. Baseline 3 is appropriate given the partial schema coverage and the description's lack of added meaning.

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 opens with a specific verb+resource: 'Renames an existing sheet in a Tabulya spreadsheet file.' That clearly separates it from siblings like sheets_duplicate, sheets_move, sheets_delete, and sheets_color. It does not explicitly name a sibling it is not, so it falls short of a 5.

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?

'Requires edit permission' and 'The new name must be unique within the file' establish prerequisites, which is real context. However, there is no explicit statement of when to use this versus alternatives (e.g., duplicating with a new name), so usage guidance remains implied rather than spelled out.

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