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

Beyond the annotations, the description reveals critical behavior: the request body is passed through unchanged, responses include cited source URLs, billing is $0.001 per successful result with specific non-billing conditions, and latency expectations differ by source type. This is exactly the kind of operational detail agents need and it is consistent with readOnlyHint/idempotentHint.

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?

Four dense sentences, each adding unique value: first defines the action and passthrough, second explains the response, third addresses billing, and the final covers latency and timeout. No wasted words and the most important constraints are front-loaded.

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?

Given the complexity of the tool and the rich schema plus output schema, the description is complete: it covers endpoint, request behavior, response contents, billing semantics, latency expectations, and client timeout guidance, while the schema covers parameters and the output schema handles return format. 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 schema already documents each parameter and its source-specific behavior, including enum values. The description adds context that sources accept subsets of parameters and that the body passes through unchanged, but it does not add parameter-level meaning beyond the schema. Baseline 3 is appropriate.

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 names a specific verb and resource (Synchronous passthrough to the upstream Oxylabs Realtime endpoint (POST /v1/queries)) and states the functional outcome: tracking how a brand or product is surfaced and cited across AI answers. It also naturally distinguishes itself from sibling tools since none of the listed siblings target AI answer engines.

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 gives clear operational context: pick a source via `source`, pass through the parameters that source expects, and use a client timeout of at least 90s due to source-specific latency. It does not explicitly contrast this tool against alternative sibling tools, but no sibling offers overlapping functionality, so an explicit when-not is not necessary.

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