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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, and the description adds substantially more: the exact auth mechanism (Bearer Supabase token, agent API key refused), the pending-partner empty-result behavior, and the row shape returned. This is meaningful context an agent cannot get from structured fields.

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?

Front-loaded with purpose, then eligibility, auth, output fields, and next step in a logical order. The eligibility clause is a long, punctuation-heavy run-on that takes effort to parse, but no sentence is padding.

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?

With no parameters and no output schema, the description carries the full load and does so: it specifies auth, eligibility filtering, absent-result behavior, returned fields, and the natural follow-up tool. Nothing needed to call it correctly is 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?

Zero input parameters, so the baseline is 4; there is nothing schema-level to explain. The description does cover the implicit request-level requirement (Authorization header) that the empty schema cannot express.

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?

States a specific verb+resource (list the shops the signed-in person may read) and precisely defines the two qualifying conditions (approved partner with proven domain, or approved registration contact). It distinguishes scope implicitly from the public catalog tool via 'signed-in person', but never names list_shops as the sibling alternative, so full differentiation is left to inference.

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?

Gives clear context for use (the caller must be a signed-in person with a Supabase token; 'a pending partner sees nothing here' and 'an agent API key is refused' set explicit preconditions). It also points to the follow-up call, get_shop_statistics with a slug. It stops short of an explicit when-not/alternative-vs-list_shops statement.

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