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

Annotations already cover read-only, idempotent, non-destructive and open-world semantics, so the safety profile is handled. The description adds real behavioral value beyond that: results are free with no account required, and the two-call discovery flow (no args to list roles, then role to get a shelf) is spelled out.

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 operational content is front-loaded and each sentence carries the role list, the card taxonomy, or the call pattern. It is somewhat verbose with marketing phrasing ('the front door of brickandmortar.dev') and a slightly redundant example block, but nothing is truly wasted.

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?

Because an output schema exists, return values need not be described, and the description instead fills the real gaps: role enumeration, the card categories, the two-step invocation pattern, and the cost/auth model. An agent has everything needed to call this correctly as a first step.

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 coverage is 100%, so the baseline is 3, but the description adds actual semantics: the intended sequencing (call with no arguments first to learn role ids), and the fuzzy-vs-exact distinction implied by 'who' versus 'role'. It clarifies workflow rather than merely restating 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 states a concrete retrieval verb and resource: it returns the list of supported roles when called with no arguments, or the 'shelf' of cards for a given role. It is clearly the discovery entry point, though it names no sibling tool by name, relying instead on the tagline 'front door' to differentiate itself.

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 routing guidance: 'Call this FIRST when someone says what they do', plus the fallback instruction to ask the user what they do if unspecified. It also states the no-args vs. role argument behavior, so the agent knows exactly which call shape to use at which moment.

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