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

Annotations already cover the safety profile (readOnlyHint, idempotent, non-destructive), so the bar is lower. The description adds the key behavioral fact that invoking this tool is a dead end and the correct action is to re-route, which is genuinely useful context beyond the 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?

A single sentence, front-loaded with the disqualifying fact and then delivering all three destinations. Zero waste and perfectly sized for a redirect stub.

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 zero required parameters and no output schema, the only thing an agent needs is to be told not to call this and where to go instead, which the description delivers completely. Nothing actionable is missing.

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% and the single 'preset' parameter is already documented as ignored. The description's 'Not a standalone tool' reinforces that the argument is inert, but adds no syntax or value meaning beyond the schema — baseline 3 is correct.

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 immediately declares 'Not a standalone tool' and defines the tool's actual function as a router to three named alternatives. The verb+resource of the tool's own name is never fulfilled by the tool itself, but the agent knows exactly what this definition is for and can distinguish it from every sibling it names.

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?

Names three concrete alternatives (get_trending_stocks, screen_stocks, screen_stocks_technical) and pairs each with the condition that selects it (ready-made movers, custom fundamental screens, technical screens). This is explicit when-to-use routing with nothing left to inference.

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