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

Annotations already declare readOnlyHint=false and destructiveHint=false, and the description goes well beyond them: it discloses the two-phase proposal flow, the exact return signal ('confirmation_required' with action_id and plan_token), and that the write only lands after confirm_action. That is precisely the behavioral context an agent needs before invoking a mutating tool.

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?

Front-loaded with the action and required parameters, then optional parameters, then the confirmation rule. The 'CONFIRMATION:' block is slightly dense and capitalized, but every sentence carries operational information with no 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?

For a seven-parameter write tool with no output schema, the definition covers required vs optional inputs, enum/default semantics, ownership precondition, and the full confirmation lifecycle. Nothing an agent needs in order to call it correctly is missing.

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?

With schema description coverage at 0%, the description carries the full burden and mostly does: it names all seven parameters and adds meaning the schema cannot, such as the currency default of EUR, the 3-letter format, and the priority labels (1=low, 2=normal, 3=high). It omits constraints present in the schema (url maxLength 1000, price minimum 0, wishlist_id accepting integer or string), so it is strong but not exhaustive.

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 an item to one of the caller's wishlists') with a clear ownership scope ('caller's'), which separates it from create_wishlist and list_wishlist_items without needing their schemas. It stops short of naming any sibling explicitly, so it is clear but not maximally differentiating.

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 the precondition ('the wishlist must belong to the caller') and routes the agent forward to confirm_action after a proposal. It does not say what to do if the caller has no wishlist yet (create_wishlist) or how this differs from the other add_* tools, leaving some alternatives implicit.

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