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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the useful constraint that only a single card is added per call, but says nothing about duplicates, auth requirements, or what happens if the card is already wishlisted.

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 very short sentences with the core action front-loaded and no filler. The second sentence is informal but does carry a real constraint, so it earns its place.

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 mutation tool with no output schema and zero parameter documentation, the description is too thin: it leaves the language parameter, duplicate handling, and success/failure behavior entirely unexplained.

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 0% and neither parameter is documented in the schema. The description implies cardId is a single card identifier but never explains the optional 'language' parameter or the expected ID format, so it does not compensate for the coverage gap.

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 ('Add ONE card to the wishlist') and the emphasis on ONE plus 'Not a catalog dump' signals it is a single-item operation, which separates it from bulk-style siblings. It does not name a specific sibling such as add_card or wishlist_mark_acquired, so differentiation is only partial.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no mention of the obvious alternatives (add_card, wishlist_mark_acquired, list_wishlist). The only implied guidance is 'one card at a time', which an agent must infer from the capitalized ONE.

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