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

Annotations already declare readOnly, non-destructive, non-open-world, so the safety profile is covered. The description still adds real behavioral value beyond them: uniqueness is verified by a solver, the puzzle is playable in-chat with pencil notes, and a PDF with answer key is produced. It stops short of stating latency, size limits, or how the two output forms are returned, which keeps it off a 5.

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?

Two sentences, front-loaded with the usage trigger before the capability list and the exclusions last. The parenthetical keyword string ('sudoku generator, printable sudoku with answers, easy sudoku for kids, hard sudoku') is slightly redundant padding, but it is the only real waste in an otherwise tight definition.

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, yet the description still tells the agent what the user actually receives: an in-chat playable grid and a printable PDF with answer key. Combined with the scope limits (9x9 classic only) and all-defaults parameters, an agent has everything needed to call this correctly on the first try.

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 each parameter already carries an example plus enum semantics, so the schema is doing the heavy lifting. The description reinforces the difficulty axis ('easy, medium or hard') and the existence of a printable PDF, but adds nothing about seed reproducibility, paper size, or title beyond what the schema states. Baseline 3 is appropriate.

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 concrete verb and artifact ('Generates a classic 9x9 sudoku') and enumerates the delivered outputs (chat-playable puzzle, printable PDF with answer key). The resource is unambiguously a sudoku, which separates it cleanly from the crossword and word-search siblings without needing to name them.

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 states the triggering intent ('when the user wants a new sudoku puzzle to play or print') and then explicitly excludes adjacent requests: solving an existing puzzle, explaining strategies, and 4x4/6x6/variant grids. That is an explicit when/when-not pair, so an agent has no inference left to do.

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