Tick off or change shopping list items

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

The description discloses the partial update behavior: 'Only the given fields are changed; the rest of each item is preserved.' This adds value beyond the annotations (readOnlyHint=false, destructiveHint=false), which only indicate non-read-only and non-destructive nature. No contradiction with annotations.

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: the first states the purpose, the second adds a critical behavioral note. No redundant words, front-loaded with the primary action. Every sentence earns its place.

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 the tool has 5 parameters (2 required, 3 optional), no output schema, and annotations present, the description covers the core behavior and partial update guarantee. It could mention idempotency or that multiple items are updated simultaneously, but the current description is fairly complete for a simple mutation tool.

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 baseline is 3. The description adds global semantics: 'Only the given fields are changed; the rest of each item is preserved.' This clarifies that the tool performs a partial update, which is not explicitly stated in the individual parameter descriptions.

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 the verb 'changes' and the resource 'shopping list items', with a specific common use case 'ticking them off'. It distinguishes from sibling tools like 'add_shopping_list_items' and 'delete_shopping_list_items' by implying updates to existing items.

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 implies usage through the phrase 'most often ticking them off', but it does not explicitly state when to use this tool versus alternatives such as 'add_shopping_list_items' or 'delete_shopping_list_items'. No when-not-to-use or alternative guidance is provided.

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