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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds meaningful context by revealing that the result is a documentation page/section rather than a structured list, and that family restricts to only that family's section of the same page. No contradiction with 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 two sentences and about 20 words, with the core resource identified first and the family-filtering behavior immediately after. Every phrase earns its place; there is no repetition or filler.

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?

Given the tool's low complexity, one optional parameter, and strong annotations, the description is nearly complete. It specifies the source page and the effect of the family parameter, though it does not describe the return format beyond calling it a page; this is a minor gap for a simple read-only listing tool.

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 only parameter, family, is fully documented in the schema with an enum and a description ('Restrict the list to one pattern family'). The description's 'only that family's section of the same page' adds slight nuance but mostly restates what the schema already communicates, 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 clearly identifies the tool as exposing the pattern catalogue and decision guide at /patterns/index.md, with optional family-based filtering. It does not explicitly distinguish this from siblings like get_pattern or search, but the resource and scope are specific enough for an agent to understand what it does.

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 implies the tool should be used when the agent needs the pattern catalogue or a family-specific section of it. However, it provides no explicit guidance on when to prefer siblings such as get_pattern for a single pattern or search for targeted retrieval.

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