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

Annotations declare the safety profile (readOnly=false, idempotent=true, destructive=false) but cannot express the mandatory two-phase preview/confirm protocol. The description supplies exactly that non-obvious behavior, including that the first call is non-committing and returns a confirm_token, which is the single most important thing an agent must know here.

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 sentences, zero padding, with the tool's purpose front-loaded and the two-step protocol immediately after. Every clause carries information the agent needs.

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 no output schema, the description sensibly explains what the first call returns (a preview plus confirm_token) and what to do with it. It could add a bit more on what the preview contains or whether moving an existing bottle affects its collection status, but nothing essential for correct invocation 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?

Schema coverage is 80%, so most parameters are already documented. The description still adds selection semantics beyond the schema: expression_path or name for a new bottle, bottle_id to move an existing one, and the confirm_token handshake ('call again with identical arguments plus this token').

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 ('put a bottle on your wishlist') and enumerates the two supported input modes (a new bottle via expression_path/name, or an existing bottle_id). An agent can distinguish this from add_to_collection and wishlist_remove purely from the description.

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 clear operational context: 'the first call only previews', 'show the preview to the user', and 'repeat the call with confirm_token only after they agree'. It also implies which parameter selects which path. It stops short of naming sibling alternatives (e.g. add_to_collection) or saying when not to use this tool.

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