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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), so the description's job is to add operational context, which it does: a candidate routing prompt (v9-eval-disjoint-examples) is live on EVERY call here, results are compared against the stable router, and there is no fallback. It stops short of describing latency, cost, or error behavior.

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?

Front-loaded with the key differentiator and reasonably tight, though the closing sentence about falling back 'to nothing' is a slightly roundabout way of saying it works standalone.

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 with no output schema, the description notes the response shape matches ask_pipeworx and explains the experimental routing context. It leaves the actual return contract to the sibling tool, which is a minor gap but acceptable here.

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% and all eight parameters (the question plus seven aliases) are documented in the schema itself. The description adds no argument-level guidance, 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?

States a specific verb+resource (a beta universal router with the same 6,453 tools, arguments, and response shape as ask_pipeworx) and explicitly distinguishes itself from the sibling ask_pipeworx, which serves the candidate prompt to only a slice of traffic.

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?

Gives an explicit when-to-use rule: 'Use it exactly like ask_pipeworx when you want the newest routing,' names the alternative, and frames the tradeoff (experimental edge vs. stable router). It even preempts a misconception by clarifying there is no fallback.

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