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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds value by specifying exactly what is not performed (diagnosis, order creation) and what the routing outcome is, all consistent with the read-only annotation. No contradiction.

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?

Two efficient sentences with zero waste. The routing action and three outcomes are front-loaded, with the safety negations placed immediately after. Every clause earns its place.

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 single-parameter tool with 100% schema coverage and strong annotations covering the safety profile, the description is nearly complete. Without an output schema, it usefully conveys the conceptual return (a routing decision among three defined options). It could name sibling tools but nothing essential for invoking it correctly 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% — the single 'summary' parameter is fully described in the schema with length constraints and content rules. The description's 'sanitized task summary' phrasing reinforces what the schema already states but doesn't add substantive new meaning, so the baseline of 3 is appropriate.

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 (route) with a clear resource (sanitized task summary) and enumerates the three concrete outcomes (fixed offer, broader Zinvyl service, scope reduction). This is specific enough to convey what the tool does, though it doesn't explicitly name siblings to differentiate itself.

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 exclusions 'performs no diagnosis and creates no order' provide clear when-not guidance that helps an agent rule out this tool for diagnostic or order-creating tasks. However, it doesn't name alternative tools or state positive conditions for choosing it over siblings like prepare_purchase_route.

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