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

Beyond the annotations, the description discloses meaningful behavior: personal adds are immediate and private to the person, household adds are shared via the Hem card, and duplicate items already present are not added again. This goes past what the annotation hints about safety, though the interaction between "not added twice" and idempotentHint=false, and what a successful call returns, are not addressed.

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-loads the destination/fallback semantics, with each sentence carrying information. Some phrasing borrows product-insider metaphors ("a card they tap in Hem") that cost the reader more than they return, but there is no padding or repetition.

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 three-parameter mutation with no output schema, the description covers destination choice and duplicate handling well. It stops short of stating what a successful call produces or how partial failures are reported, and names no sibling tool for follow-up actions such as checking the list, so an agent is left to infer the result shape.

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 100%, so the baseline is 3, but the description adds real meaning on top: it explains what happens when `to` is omitted (fallback to last choice, then household when one exists), which the schema does not. It adds little on the `household` parameter beyond what the schema already says about name or householdId.

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 conveys a specific action with specific objects: adding items to a personal list versus a household shopping list, with the concrete example "Lägg mjölk på listan". The purpose is inferable and fairly precise, but it opens with an embedded scenario (and metaphors like "a card they tap in Hem") rather than a plain statement of the tool's verb and resource, and it never names a sibling for contrast.

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 described indirectly through the `to` parameter and a clear fallback chain (last chosen, otherwise household when one exists), which helps an agent decide where an add lands. However, there is no explicit "use this when…" guidance and no mention of alternatives such as check_shopping_items for viewing a list, so the routing guidance is implied rather than stated.

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