get_hydration

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

With no annotations, the description carries the burden, and it does explain that the operation returns water intake and goal progress. However, it does not disclose any caveats such as data availability, timezone assumptions, or behavior when no data exists for the date, though the read-only nature is implied by 'Get.'

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 two short sentences with no filler. The date format is front-loaded, and the return values are stated in the second sentence, making it easy to scan and act on.

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 low complexity (one required parameter, no nested objects) and the existence of an output schema, the description is largely complete. It does not discuss when to use it versus get_daily_summary or get_goals, but hydration is distinct enough among the siblings that this is a minor gap.

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 schema only defines 'date' as a string with 0% description coverage, but the description compensates fully by specifying the required format '(YYYY-MM-DD)'. This gives the agent the exact syntax needed for the single required parameter.

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 resource ('hydration data') and the exact verb ('Get') plus the temporal scope ('for a date'). It also specifies the return content ('water intake in ml and progress toward daily goal'), and no sibling tool covers hydration, so it is easily distinguishable.

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 gives clear context for when to use the tool: when hydration data for a specific date is needed. It does not explicitly name alternatives or exclusions, but none of the sibling tools are hydration-specific, so this is not a significant gap.

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