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

Annotations already declare the full safety profile: readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=false. The phrase 'and/or' usefully signals partial-update semantics, which is real added value. However, it omits whether passing null clears the description, whether omitted fields are left untouched, and any auth or error behavior.

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?

A single tight sentence with the verb and target up front and no filler. It is appropriately sized, though it is so terse that it leaves useful information on the table rather than being maximally informative per word.

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?

Given a 4-parameter mutation tool with no output schema and annotations that already cover safety and idempotency, the description is close to sufficient: the agent can infer the updatable fields and their optionality. The missing piece is the null-clears-description behavior, which matters for an optional nullable field.

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 only 25% (just wishlistId = 'UUID'), so the description must compensate. It names all three mutable fields, which covers the remaining parameters at a name level, but adds no semantic detail: no mention that the theme enum is a fixed set of values, no length bounds, and no explanation that null clears the description.

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?

Names a specific verb ('Changes') and the exact mutable fields (title, description, theme) on a clearly identified resource ('one of the user's wishlists'), which separates it from update_item and create_wishlist. It stops short of explicitly naming the sibling it supersedes or the read counterpart get_wishlist.

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 states only what the tool changes, with no when-to-use context, no prerequisites (e.g. ownership of the wishlist), and no reference to alternatives such as update_item for item-level edits. An agent must infer the correct invocation scenario from the name alone.

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