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

No annotations are provided, so the description carries the burden. It usefully discloses cost ($0.01 per call, USDC on Base) and the stopword-filtering behavior, but says nothing about return format, ordering, or what happens on empty/non-Persian input.

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 front-loaded sentence with the core purpose first and parenthetical qualifiers for filtering and pricing. No wasted words, though the trailing pricing parenthetical slightly interrupts the core statement.

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 no-annotation, no-output-schema tool with three parameters, the description covers purpose, cost, and filtering but omits return shape (keyword list? scores?) and the meaning of 'limit'. It is adequate but leaves real gaps for correct invocation.

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?

The description adds no information about any parameter. Schema coverage is 67%, and the undocumented 'limit' parameter (no schema description, no enum) is left completely unexplained in both places, so the description fails to compensate for that gap.

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 (extract) and resource (frequent keywords) with a qualifier (stopword-filtered, Persian text). It is easily distinguished from siblings like fa_stats or fa_similarity, which serve different purposes.

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 purpose implies when to use it (keyword extraction from Farsi text), but there is no explicit when/when-not guidance or reference to an alternative sibling such as fa_stats. Usage is inferable rather than stated.

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