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

Annotations already flag destructiveHint=true and idempotentHint=true, but the description adds genuine meaning beyond that: it discloses patch semantics ('only the given fields change') and the null-clearing convention for brand/notes, which explains the otherwise opaque destructive hint. It stops short of saying what is returned or whether a missing item errors out.

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 front-loaded sentence with the resource and mutable fields first, followed by a tight parenthetical that carries the two highest-value behavioral facts. No filler or repetition of structured fields.

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 four-parameter mutation with full annotation coverage and no output schema, the description covers the mutable surface and the null-clearing behavior adequately. It leaves the return value and failure mode for an unknown itemId unstated, which is a minor gap given no output schema exists.

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 only 25%, with just itemId documented, so the description carries real weight here. It explains what name/brand/notes mean in the edit and, critically, that passing null clears brand/notes — a semantic the schema expresses only as a bare anyOf string/null with no explanation.

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 (edit) and resource (shopping-list item) and enumerates the mutable fields: name, brand, notes. This implicitly separates it from the sibling stackwell_update_shopping_item_status, which handles status rather than content, though that sibling is never named.

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?

Usage is implied by the field list — an agent can infer this is for content edits and not status changes or deletion. However, there is no explicit when-to-use statement, no mention of when to prefer stackwell_update_shopping_item_status, and no prerequisites noted.

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