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

Annotations declare the tool is not read-only, is idempotent, and not destructive. The description adds context that the list is synced and partners see every change, that keys must be copied exactly (never invented), and that it returns the updated list. This goes beyond annotations with useful behavioral details.

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 dense but well-structured, front-loading the core purpose, then usage rules, parameter semantics, alternatives, and return behavior. Each sentence conveys a distinct requirement without redundancy, earning 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's complexity (4 operations, no output schema), the description covers all necessary aspects: exact operation semantics, key provenance, user consent requirement, the partner visibility effect, the alternative tool for recipes, and the return value. Nothing critical is missing.

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?

With zero schema descriptions, the description fully compensates: it explains that check/uncheck/remove take exact keys from get_shopping_list, while add takes plain lines as spoken by the user. This gives the agent precise guidance on how to fill each parameter correctly.

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 tool changes the synced shopping list with specific operations (cross off, un-cross, remove, add). It also references get_shopping_list for keys and identifies add_to_shopping_list as the alternative for recipe ingredients, distinguishing this tool from its siblings.

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?

It explicitly says 'Call it ONLY on the user's explicit ask' with concrete examples, and directs recipe-ingredient additions to add_to_shopping_list. This gives clear when-to-use and when-not-to-use guidance, including the prerequisite of obtaining keys from get_shopping_list.

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