set_selection_items

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

With no annotations provided, the description carries the full burden and does an excellent job. It discloses the gating by writes_enabled, the replace semantics, that an empty list empties the selection, that products not in favorites are silently dropped, and advises checking the returned items count.

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?

The description is compact and front-loaded, starting with the gate and core behavior. Every sentence earns its place, including the caveat about favorites and the silent drop, without any redundant fluff.

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?

The tool modifies a resource with side effects, so prerequisites, behavioral caveats, and validation guidance are all present. An output schema exists, so return values are not required. The description covers everything needed to call the tool correctly and confidently.

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%, so the schema already clearly documents both parameters: skus are the full list, not an addition, and uuid comes from list_selections()[].uuid. The description reinforces the replacement behavior but does not add significant new parameter-level meaning beyond what the schema provides.

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 clearly states a specific verb (Set), resource (which products a selection holds), and scope (as the whole list). It distinguishes itself from sibling tools add_to_selection() and remove_from_selection() by explicitly naming them as alternatives.

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 explicitly says when to use this tool vs alternatives: for 'add this'/'take that out' use add_to_selection()/remove_from_selection(), while this one replaces the whole list. It also gives the prerequisite that products must be in favorites first.

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