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

Annotations declare readOnlyHint=false, openWorldHint=true, destructiveHint=false, so the agent already knows this reaches outside the system. The description adds genuinely useful, non-structured context: the output is third-party AI/web content and must be treated as data, not instructions — a prompt-injection warning. However, it says nothing about cost/billing, latency, or what 'structured output' actually contains, which is conspicuous for a paid external AI call.

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 sentences with zero filler; the purpose is front-loaded and the safety caveat follows immediately. Nothing is repeated from the schema or annotations.

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 a complete schema and partial annotations, most invocation mechanics are covered, so the description is minimally viable. But for an external, likely billable AI call with a nested include object and no output schema, it omits cost implications and any sense of the returned structure, forcing the agent to infer 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 description coverage is 100%, so every parameter (state, prompt, country, include) is already documented in the schema, including the state/country restriction and the extra-output flags. The description only hints at localization ('in many regions') and adds nothing the schema does not already contain. Baseline 3 applies.

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 ('Get structured output from Perplexity AI') and names the topic scope (brand, products, any topic) plus a regional dimension. The vendor name implicitly distinguishes it from the sibling AI-query tools (chatgpt, gemini, grok, copilot), though the differentiation is by provider name rather than by stated capability difference.

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 says what it can be used for ('your brand, your products or any other topic, in many regions') but never says when to choose it over chatgpt, gemini, grok, or google_news, and gives no exclusions or prerequisites. There is no 'use this instead of X when Y' guidance.

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