Update Fitatu User Settings

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

Annotations already indicate readOnlyHint=false, destructiveHint=true, and idempotentHint=true. The description adds valuable context: it mentions partial updates, the ability to combine energy and water, and that omitted supported settings and all unsupported settings are preserved. This goes beyond the annotations by clarifying the non-destructive nature to unaffected settings. It does not contradict the annotations; destructiveHint refers to modifying target values, which is consistent with the update behavior described.

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 three concise sentences, each earning its place. The first sentence states the core purpose; the second enumerates capabilities; the third clarifies preservation behavior. It is front-loaded with the main action and avoids redundant details that are already in the schema. No fluff or extraneous information.

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 moderate complexity (partial updates, multiple optional parameters, two modes), the description covers the essential aspects: what it updates, how modes work, and that omitted settings are preserved. The schema provides detailed field-level info, and an output schema exists, so the description does not need to explain return values. It lacks explicit mention that at least one parameter is required, but the schema's minProperties=1 covers that. Overall, it is sufficiently complete for correct invocation.

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 schema fully documents each field. However, the description adds semantic value beyond the schema: it clarifies that energyTarget can be a 'complete manual energy target' or switch to 'automatic mode', and explicitly states that energy and water can be combined in one update. It also explains preservation of omitted settings, which is not in the schema. This meaningful addition justifies a score above the baseline of 3.

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 states a specific verb ('updates') and resource ('authenticated Fitatu user's supported settings'), and lists distinct capabilities (manual energy target, automatic mode, water serving size, combined updates). It clearly differentiates from the sibling get_user_settings, which reads settings, while this tool updates them. The phrasing is unambiguous and leaves no room for confusion about the tool's role.

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 by stating it updates settings and enumerates what it can change, making it obvious this is the tool to use for modifying Fitatu user settings. It does not explicitly mention when not to use it or name alternatives, but given the sibling list, there is no other update-settings tool. The context is clear, though it could explicitly state 'use this to change settings' rather than leaving it implied.

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