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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered. The description adds genuine context beyond that by disclosing the vocabulary the completions draw from (product, font, style, category names), but it says nothing about ordering, empty results, or matching semantics (prefix vs substring).

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 tight sentences, front-loaded with the action and followed by examples and scope. No filler, no restatement of the title, and every clause carries information an agent can act on.

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 two-parameter read-only lookup with a fully described schema and no output schema, the description gives enough to call it correctly and to anticipate the kind of strings returned. Minor gap: it doesn't describe how results are shaped or ordered, which matters slightly since no output schema exists.

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 100% and both parameters are documented there, including a default for size, so the description need not carry this load. Its 'scri' example mirrors the schema's own prefix examples, adding little beyond what structured data already provides.

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 ('Return search-term completions for a partial query') and immediately grounds it with concrete examples ('scri' -> 'script', 'script font'). The final clause names the domain of coverage (product names, font names, styles, categories), which clearly separates it from sibling search_products, which returns results rather than completions.

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 description implies usage (feed it a partial query to get suggestions) but never states when to choose it over search_products or suggested_searches, nor any prerequisite such as 'use before committing a search'. An agent can infer the typeahead scenario but gets no explicit routing guidance or exclusions.

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