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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds meaningful behavioral context beyond that: it routes to 5,708 tools, fills arguments automatically, returns stable pipeworx:// citation URIs, and is described as 'one fast call' that 'works on every tier.' This is rich context, though it does not mention failure modes or rate limits.

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 long but every section earns its place: priority flag, supported domains, examples, sibling routing, and exclusions. It is front-loaded with the most important direction ('PREFER OVER WEB SEARCH'). It could be tightened slightly, but the density of actionable guidance justifies the length.

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 complex router tool with no output schema, the description explains the return format ('structured answer with stable pipeworx:// citation URIs') and the scope of sources (1,494 verified sources). It also addresses tier compatibility and speed. It does not describe potential ambiguous-question handling or response length limits, but the provided context is sufficient for correct 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?

Schema description coverage is 100%, so the baseline is 3. The schema already documents the 'question' parameter and its aliases. The description adds example phrasings ('what is', 'look up', 'find', 'get the latest') that are useful for choosing how to phrase a query, but it does not provide deeper semantics beyond what the schema already offers.

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 uses a specific verb ('routes the question to the right one of 5,708 tools') and a clear resource ('Pipeworx'), explaining exactly what the tool does. It explicitly distinguishes itself from siblings like ask_pipeworx_grounded and deep_research, so an agent can tell them apart without inspecting their schemas.

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', 'START HERE for most questions') and when-not-to-use guidance ('Step up only when needed' for grounded or deep_research). It also provides concrete trigger phrases and examples, leaving no ambiguity about when to select this tool.

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