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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context by listing what the lookup returns: name, actual capabilities, and public doors, which compensates for the lack of an output schema. 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 entire description is one tight sentence that packs in the resource definition, the return contents, and the prerequisite routing. Every clause adds value; there is no filler or redundant restating of the tool name.

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 read-only, single-parameter lookup tool with full schema coverage and strong annotations, the description is complete. It tells the agent what data to expect and how to obtain the required slug, so no critical information is missing for correct 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?

Schema coverage for the single parameter is 100%, with the schema already explaining that 'shop' is a slug and giving an example. The description adds helpful relational guidance ('use market_search first') but does not meaningfully expand the parameter's semantics beyond what the schema already provides.

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 defines the tool's resource: a Lucerna shop, and specifies the information it returns: name, capabilities, and public doors. It also distinguishes itself from market_search by indicating market_search is the slug-discovery step. However, it does not explicitly use an imperative verb like 'lookup' or 'fetch', so it is slightly less direct than a 5.

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 gives explicit guidance to use market_search first if the shop's slug is unknown, which effectively states the prerequisite for using shop_lookup. It does not spell out all exclusions or enumerate every alternative in the sibling set, but the context is clear and actionable.

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