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

With no annotations, the description carries the burden and does disclose non-obvious behavior: letters are sampled by language frequency, accents are honored per language, and the words argument prevents the filler from accidentally spelling a hidden word. It is silent on determinism (seed semantics live only in the schema) and on permissions/side effects, minor gaps for a pure computation tool.

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 tight sentences with no filler; the input contract and the words-safety rationale are front-loaded. Everything stated earns 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?

For a 6-parameter tool with no output schema, the description gives enough to call it correctly (source of the grid, language/accent behavior, word-safety). It could say explicitly that a fully populated grid is returned, but that is easily inferred from 'completes' and 'fills them'.

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 the schema descriptions already explain grid format, lang default, seed repeatability, the empty marker, and the words rationale. The description largely restates that ('pass the puzzle's words so the filler never creates an extra copy'), so the baseline of 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 names a concrete verb and resource (fills the empty cells of a word-search grid), states the exact input contract (grid from generate_word_search, '-' marks empties), and names the sibling it pairs with. An agent can distinguish this filler from generate_word_search without opening a schema.

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 clearly places the tool in a workflow: take the grid produced by generate_word_search and pass that puzzle's words along. It gives a usage condition (words are passed so no duplicate word is created) but never states explicit exclusions or alternatives for when not to call it.

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