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

The description discloses an important behavioral trait: omitted fields remain unchanged, meaning this is a non-destructive partial update rather than a full replacement. But with no annotations, it carries the full burden and does not mention validation, response format, atomicity, or what happens when fields are explicitly set (e.g., replacement of free-form text is only noted in the schema, not here).

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?

One compact sentence of 12 words that front-loads the action and subset behavior, then states the preservation guarantee. There is no filler or repetition of schema information, so every word serves a purpose.

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?

This is a mutation tool with 12 parameters, no annotations, and no output schema, but the description only provides a high-level operation guarantee. It does not mention what the tool returns, whether changes take effect immediately, or how it relates to sibling tools such as set_voting_deadline, favorite_recipe, or assemble_online_grocery_order. For an agent to confidently invoke this tool, the partial-update semantics help but many operational details are 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?

The description adds meaning by establishing that all parameters are optional and that omitted ones keep their current values, which applies across the 12-parameter set. However, schema coverage is only 58%, and the description does little to explain the undocumented parameters like plan_day, servings, grocery_store, recipes_per_week, or votes_per_member; it only vaguely groups them as 'preferences prompt and settings.'

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 uses a specific verb ('Update') and identifies the resource as 'the preferences prompt and settings.' It is clearly distinguished from siblings like get_recipe_preferences (read-only) and update_recipe (recipes, not preferences), so an agent can tell what this tool operates on.

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 clearly communicates partial-update semantics ('any subset', 'Omitted fields are unchanged'), which implies when to use this tool. However, it does not explicitly name alternatives or exclusions, such as get_recipe_preferences for reading or set_voting_deadline for deadline changes, leaving the decision somewhat to inference.

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