yoto_list_cards

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

Annotations already declare readOnlyHint=true; the description's 'No write operation' is consistent but redundant. It does add the 'authenticated user’s' scoping, which clarifies whose cards are returned, though it provides no detail on pagination, sorting, or output shape.

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 short front-loaded sentences with no unnecessary elaboration. The first sentence communicates the core purpose immediately; the second reinforces read-only behavior, though it is somewhat redundant with the readOnlyHint annotation.

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 zero-parameter, read-only list operation, the description is substantively complete: it identifies the resource and the authenticated scope, and annotations cover safety. It does not describe return fields or pagination, but no output schema exists and the operation is simple enough that this is a minor gap.

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?

The tool has zero parameters and schema coverage is 100%, so there is no parameter documentation burden. The baseline of 4 for parameterless tools applies, and the description correctly focuses on behavior rather than inputs.

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 ('Read') and resource ('authenticated user’s MYO cards'), making the operation's scope unambiguous. The name yoto_list_cards is further clarified as a list operation, distinguishing it from yoto_get_card without needing to open the schema.

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 implies the tool is for retrieving the authenticated user's MYO cards, but it does not explicitly say when to prefer it over siblings like yoto_get_card or yoto_list_devices. There is no exclusion guidance or alternative routing, leaving usage mostly to inference.

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