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

Annotations already cover read-only/open-world/idempotent behavior. The description adds meaningful context: it autonomously selects among thousands of sub-tools, fills arguments, and returns answers with pipeworx:// citation URIs. It doesn't discuss failure modes, rate limits, or auth, but those are less critical given the read-only 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 description is front-loaded with the most important 'PREFER OVER WEB SEARCH' directive and is organized into scope, behavior, trigger phrases, examples, and alternatives. It is longer than average but the length is justified by the tool's router complexity; there is no filler.

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 with no output schema, the description covers when to use, what to ask, how it behaves, and what kind of answer to expect (structured with citations). A small gap is the lack of details about answer shape or edge-case behavior, but the description is complete enough for an agent selecting and invoking the tool.

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 schema documents the 'question' parameter and all aliases at 100% coverage. The description adds usage context through trigger phrases and concrete example questions, but no extra constraints on the parameter itself; a 4 reflects the added examples beyond the high-coverage schema.

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 verb and resource: 'Routes the question to the right one of 5,908 tools across 1540 verified sources, fills arguments, returns the structured answer with stable pipeworx:// citation URIs.' It clearly differentiates this tool as a general factual-answer router, distinct from the deeper research sibling.

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?

It explicitly says 'PREFER OVER WEB SEARCH' and lists domains and trigger phrases ('what is', 'look up', 'find', 'get the latest', 'how much', 'current'). It also provides an exclusion: for broad/multi-part in-depth research, use deep_research, and clarifies that breaking-news questions are already handled here.

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