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

Annotations already declare readOnly/non-destructive, and the description adds genuinely non-obvious semantics beyond them: there is no parent-grants-the-children cascade, permissions must be passed exactly as named, and the catalogue is global rather than merchant-specific. These are the kind of facts that change how an agent calls the dependent create_role/update_role tools.

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?

Five sentences for a zero-argument tool, each carrying distinct information (purpose, downstream use, ambiguity handling, no-cascade, global scope). It is a little long and the opening could name the tool's action more directly before the 'catalogue' framing, but nothing is 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?

With no parameters, no output schema, and annotations that already cover the safety profile, the description still closes every loop an agent needs: what the data is, what it is used for, how to resolve matching ambiguity, and where to go for the merchant-specific alternative.

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 parameters, so there is nothing to document and the baseline is 4. The description usefully explains the semantics of the identifiers returned (permission id consumed by create_role/update_role), which is consumer-side meaning rather than schema repetition.

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 (the catalogue of permissions a role can be given) and pins down the exact artifact returned — 'every switch on the Roles screen, with the id create_role and update_role need'. It also explicitly distinguishes itself from the sibling hub_get_roles, which covers the merchant's *current* grants.

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 a concrete triggering scenario ('turn a request like "let her see the reports" into the right permission id') and an explicit alternative with its condition ('For what a role currently grants, use get_roles'). It even tells the agent how to resolve ambiguity (ask the merchant if two labels could both be meant).

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