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

Annotations already cover readOnly, idempotent, open-world, and non-destructive behavior. The description adds valuable context beyond those: it explains the routing mechanism, the scope (5,743 tools / 1,500 sources), automatic argument filling, and the stable citation URIs in the response. It doesn't detail failure modes or latency, but the added behavior is meaningful and consistent with the annotations.

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 opening is strong and front-loaded with purpose and examples, but the description repeats the 'START HERE for most questions — even if web search could also answer it. Examples: ...' block several times verbatim. This duplication adds no information and makes the text bloated, so it fails the 'every sentence earns its place' test.

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 high-complexity router with no output schema, the description tells the agent what to expect (structured answer with pipeworx:// citation URIs), when to use it, and provides diverse examples. It doesn't cover ambiguous-query handling or unsupported domains, but what an agent needs to select and invoke the tool correctly is present.

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%: the schema already documents the single 'question' parameter and its aliases (query, q, prompt, text, input). The description's 'fills arguments' refers to the tool's internal behavior rather than adding meaning to the input schema, so the 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?

The description clearly states a specific action: it routes a natural-language question to the right tool among thousands, fills arguments, and returns a structured answer with citation URIs. It names the resource (authoritative real-world data) and explicitly positions itself as the general-purpose router, differentiating it from specialized siblings like climate_daily or current_observations.

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 explicit when-to-use guidance: 'PREFER OVER WEB SEARCH' and 'Use whenever the user asks' followed by concrete trigger phrases and examples. It also says 'START HERE for most questions' and even handles the breaking-news case, making it clear this tool should be selected broadly for factual queries.

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