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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds minor behavioral context such as 'unique' and 'available', but does not go beyond annotations with details like pagination, limits, 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?

Three sentences deliver the purpose, usage, and target audience without any filler. The core action is front-loaded, and each sentence 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 simple list endpoint with no required parameters, the description covers what the tool does, why it exists, and how to use its output. It lacks a precise return-shape statement, but the annotation and schema coverage make it adequately complete.

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?

The compact parameter is fully described in the input schema, including behavior and token savings. With 100% schema coverage, the description does not need to add parameter details and does not, so a 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 starts with a specific verb and resource: 'List all unique planetary associations available in the database.' It clearly distinguishes itself from sibling tools by focusing on planetary associations and explicitly frames itself as an essential reference endpoint.

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?

It explicitly instructs the agent to 'Use these values with the planet filter on GET /crystals,' giving clear context for when to invoke the tool. However, it does not name or exclude alternative tools, so it has clear context but no explicit when-not guidance.

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