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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe read nature is covered. The description adds behavioral context about what the price breakdown includes (medication cost, fee, shipping, discounts) and that plan durations vary by medication. This goes beyond annotations, though it doesn't discuss rate limiting or other edge behaviors, but those are 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?

The description is three sentences, front-loaded with the purpose. Each sentence adds value: what it does, what is returned, and a prerequisite. No redundant phrases or filler. It's concise and well-structured.

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 simple read tool with an output schema, the description is complete: it covers purpose, return contents, and a prerequisite. It names supported medications and refers to medications_details for plan durations. It doesn't explain client_ip, but the schema covers that. The openWorldHint and output schema reduce the burden, so this is sufficient.

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%, so parameters are well-documented in the schema. The description adds some context by identifying the key inputs (medication, form, plan duration) and warning that plan_months values vary by medication, nudging to use medications_details. This is helpful but doesn't significantly deepen parameter understanding beyond the 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 clearly states the tool's purpose with a specific verb ('Get detailed pricing') and identifies the resource (medication, form, plan duration). It distinguishes from siblings by focusing on pricing, not availability or details. The return components are explicitly listed, making it unambiguous.

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 description provides clear usage context by instructing to 'use medications_details first' to see available plan_months values, establishing a prerequisite. It also mentions which medications are supported, implicitly covering scope. However, it doesn't explicitly name alternatives like medications_availability or state when not to use this tool, so it's not fully exhaustive.

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