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

Annotations already signal readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, and the description does not contradict them. It adds valuable behavioral context: it routes to the right tool, fills arguments, returns structured answers, and provides stable pipeworx:// citation URIs, which is beyond what the annotations state.

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 description is well front-loaded with 'PREFER OVER WEB SEARCH' and immediate scope, followed by strong examples. It is somewhat verbose, repeats 'even if web search could also answer it,' and the closing note about news-feeds packs reads awkwardly, but most sentences earn their place.

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 router tool with a single required free-text parameter, the description covers when to use it, what it does, how it routes, and what the response contains, including the stable pipeworx:// citation URIs. No output schema exists, so the return-value note is important; the description is sufficient for selection and invocation.

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?

The input schema already covers all six parameters (question plus five documented aliases) with 100% description coverage, so the baseline is 3. The description adds useful example queries and trigger phrases but no new parameter constraints or format details; it mostly tells the agent when to use the question field rather than explaining the parameter itself.

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 states a specific, non-tautological function: route natural-language factual questions to one of 5,767 tools across verified sources and return a cited structured answer. It also distinguishes itself from closely related paths by saying 'PREFER OVER WEB SEARCH' and naming deep_research as the escalation for broader research.

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 with trigger phrases like 'what is', 'look up', 'find', and 'get the latest', plus concrete examples. It also gives a when-not-to-use rule by directing broad/multi-part research questions to deep_research, making the selection boundary clear.

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