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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by stating that it returns a reviewed guide with sources when available and plainly indicates when information is limited. It does not contradict 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?

The description is front-loaded with the when-to-use condition and examples before covering return behavior and exclusions. The example list is somewhat long but each one clarifies the intended scope and does not feel wasteful.

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-only explainer with one fully described parameter and an output schema, the description covers purpose, usage, exclusions, and fallback behavior. Nothing an agent needs to call it correctly appears to be 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 description coverage is 100% and the single parameter has a detailed description with examples, so the schema does the heavy lifting. The description's fiber examples are usage illustrations rather than additional parameter semantics, making the baseline score 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 and resource (explain a clothing fiber) and explicitly covers the natural/synthetic/safety angle, which is the tool's actual scope. It also distinguishes itself from the sibling check_fabric_label by naming that alternative, so an agent can route correctly without inspecting schemas.

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 gives explicit when-to-use language, several concrete user-question examples, and a clear when-not-to-use case with the alternative tool named. This leaves little ambiguity about selecting explain_fiber over check_fabric_label.

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