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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the returned contents, including freshness ('when it was last checked') and provenance ('link... which has the dated source'), which an agent cannot infer from annotations alone.

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?

The core purpose and accepted inputs are front-loaded in the first two sentences, with fallback behavior and provenance following in a logical order. It is somewhat dense in enumerating return contents, but every clause carries information an agent would otherwise lack.

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?

There is no output schema, yet the description covers the return shape, fallback behavior for non-free tools, freshness, and where the full detail lives. For a single-parameter read-only lookup, nothing essential is missing.

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 single 'tool' parameter is already documented. The description goes further with concrete accepted formats ('ChatGPT', 'Midjourney', 'canva.com'), making clear both display names and domains work, which is more than the schema's bare 'name or website' wording.

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 specific verb+resource: 'Check whether a specific AI tool is free and exactly what its free plan includes.' It enumerates the answer surface (limits, catches, cheapest paid plan, last-checked date), which clearly separates it from find_free_ai_tools (browse) and compare_free_plans (multi-tool comparison).

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 implies the right context by describing a single-tool lookup with a name or website input, and notes the fallback behavior when a tool isn't free ('says why and suggests free alternatives'). However it never explicitly states when to reach for this instead of the sibling compare_free_plans or find_free_alternatives, leaving routing to inference.

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