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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no additional behavioral traits beyond what annotations provide, such as pagination or ordering. It is consistent with annotations, so 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?

The description is two sentences with zero filler. It front-loads the core action ('List all reference architectures'), then adds scope, returned fields, and a usage pointer. Every word 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?

Given the tool has an output schema (covering return structure), one optional parameter, and strong annotations, the description fully covers what the tool does, when to use it, and how it differs from `search`. No gaps remain for effective invocation.

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 sole parameter (locale) has full schema coverage: an enum (en/es/pt) and a description. The description adds no extra meaning for parameters, so the baseline of 3 applies where the schema does the heavy lifting.

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 'List all reference architectures' with a specific verb and resource, and enumerates the fields returned (id, slug, category, name, summary, provenance). It explicitly distinguishes from the sibling `search` tool by noting it's for browsing when you have a name, not a use case.

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 explicitly provides when to use this tool ('Use this to browse the blueprints') and names the alternative ('use `search` when you have a use case rather than a name'). This gives clear guidance on tool selection versus a sibling, exceeding basic context.

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