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

Annotations already declare readOnlyHint, so the safety profile is covered; the description still adds useful context by naming the response fields and disclosing cursor-based pagination through next_after. It doesn't mention rate limits or whether deleted registers appear, but that is a minor gap given 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?

Two tight fragments: what is returned first, then pagination note, then endpoint. No filler or redundancy; every element is useful.

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 simple read-only list tool with full schema coverage and a readOnly annotation, the definition supplies enough: resource identity, returned fields, pagination cue, and endpoint. Only the absence of any output schema means return shape is described by field enumeration rather than a formal contract, which is acceptable here.

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%, with each of the four parameters fully documented (cursor semantics, deleted flag, page_size guidance). The description's 'Paginate with next_after' adds only a pointer that the schema already explains in detail, so baseline 3 is appropriate.

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 and resource ('List registers (tills)') and enumerates the returned fields (id, name, outlet_id, is_open, open/close times, invoice numbering). This is clearly distinguishable from siblings like get_register_payments_summary, though the description doesn't name any sibling explicitly.

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?

Usage is implied: use this to enumerate tills before working with a specific register. It mentions pagination via next_after but gives no when-to-use/when-not guidance or any comparison to alternatives such as list_outlets or the register payments summary tool.

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