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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's added value is the concrete cost model (6 credits = 4 base + 2 sync surcharge, +2 for state), which is genuinely useful pre-call context not in the annotations. It omits latency/rate-limit nuance and doesn't elaborate on return structure beyond "answer with cited sources".

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: capability first, then the use case, then the cost. Every sentence carries information and the most decision-relevant fact (cost) is stated plainly.

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?

With no output schema, the description correctly characterizes the return (answer plus cited sources) and discloses the credit price and geo-targeting scope. Additional detail on response shape for the include flags would close the remaining gap, but an agent has enough to call this correctly.

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 baseline is 3; the description adds the non-obvious fact that state targeting is optional, country-restricted, and costs an extra 2 credits, which is meaning the schema alone doesn't convey. The include flags are left entirely to the schema, keeping it short of a 5.

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: submit a prompt to Perplexity and return the answer with cited sources, geo-targeted by country/state. The Perplexity naming implicitly distinguishes it from scrape_chatgpt/scrape_gemini siblings, but it never explicitly contrasts with them.

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?

"Use this to see how Perplexity answers a prompt and which brands/sources it mentions" gives a clear application context, and the state/country handling points implicitly to list_countries/list_states. No explicit when-not-use or exclusion guidance is offered.

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