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

Annotations declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false, so the safety profile is partly covered. The description adds meaningful behavior beyond that: it may either execute the call itself or return a payload, it will not override explicit values, and it degrades to candidate lists on low confidence. Missing details like cost/side-effect specifics (max_cost behavior lives only in the schema).

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 core purpose, followed by the no-override guarantee and the routing flow. Slightly redundant ('fills only the blanks' and 'explicit values are never overridden' overlap) and dense, but every clause contributes to correct invocation.

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?

With no output schema, the description carries the return contract and does so: it explains both outcomes (executed result vs ready-to-run payload) and the candidate fallback. For an open-world, executing router with nested input this is nearly complete, though edge cases like error behavior are unstated.

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 coverage is 100%, so the baseline is 3, but the description adds the governing rule that only blanks are filled and explicit values win, which clarifies how tool/skill/model/input interact. It adds modest semantic value over the schema descriptions, most of which already say 'honoured verbatim when set.'

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 and behavior: send a natural-language intent, fill only the blanks, then execute or return a use_tool payload. It explicitly distinguishes itself from the sibling use_tool by describing the division of labor between the two. An agent can tell route apart from use_tool directly from the text.

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 decision flow: 'route → if confident and complete, result is returned; otherwise use the pre-filled call with use_tool.' It also states the condition for returning candidates (low confidence or no tool fits) and reinforces that explicit values are never overridden. The alternative and its selection condition are named, not left to inference.

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