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

With no annotations, the description carries the full burden. It usefully discloses accepted sizes (4, 6, 9, 12, 16), that 0 marks empty cells, that uniqueness is reported, and that there is no cost/rate limit. It omits behavior for unsolvable, malformed, or contradictory grids and does not describe the returned solution format.

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?

A single tight sentence front-loads the operation, then parenthetically supplies the cell convention, then the uniqueness behavior and cost note. No filler.

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 one-parameter tool with no output schema, the description covers input conventions, supported sizes, and part of the return semantics (solution + uniqueness). Error/edge-case behavior remains unexplained, which is the main residual 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 coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: the schema permits any row/column length from 4 to 16, while the description narrows valid sizes to 4, 6, 9, 12, 16. That constraint is directly useful for constructing a valid puzzle.

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+resource ('solves a sudoku grid') plus the extra behavior of reporting solution uniqueness, which is more than the title conveys. It does not explicitly distinguish itself from the sibling 'sudoku', which the agent must infer is the generation counterpart.

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?

Usage is implied: supply a puzzle, get a solution. The 'free, no usage limit' note is useful context but there is no explicit when-to-use/when-not guidance or reference to the sibling sudoku tool for generating instead of solving.

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