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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds a behavioral constraint annotations cannot express: this tool is reserved for the panel and must not be invoked by the agent. It does not discuss return shape, but an output schema exists to carry that.

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 compact clauses with zero filler, and the critical constraint ('never call it yourself') is front-loaded ahead of the return behavior.

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 one well-documented parameter, full annotations, and an output schema, the only missing piece would be the invocation constraint — which the description supplies explicitly. Nothing an agent needs to avoid misusing this tool is absent.

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 description coverage is 100% and the single parameter is fully documented in the schema ('Up to 20 of the card_ids the panel was given'). The description's 'both sides' hints at how the input window maps to output but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 specific action (returns more of the cards the panel is paging through) and explicitly names the sibling it is not (list_cards), so an agent can distinguish it without opening the schema. The resource phrasing ('cards the panel is paging through, both sides') is slightly indirect but still conveys the paging-window semantics.

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 an explicit when-not ('never call it yourself') and names the alternative to use instead ('use list_cards'), plus the only legitimate caller (Flash's panel). This is exactly the routing guidance an agent needs.

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