get_hydration_data

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond the purpose line: it does not say what happens when no hydration was logged for the date, what fields the log contains, or any rate/availability caveat.

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?

A single short sentence with no filler, and the key scoping constraint (one date) is front-loaded. It is efficient, though bordering on under-specified rather than truly concise.

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?

For a one-parameter read tool with annotations covering safety and no output schema, the definition is minimally viable. It omits any indication of what the log returns or how empty days are handled, which an agent would benefit from knowing.

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% and the single cdate parameter is documented with its format and UTC basis, so the baseline is 3. The description's 'one date' phrasing reinforces the single-parameter contract but adds no format or timezone detail beyond the schema.

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 identifies the resource (hydration log) and its scope (one date), which cleanly separates it from the write-side sibling add_hydration_data. It is a noun phrase rather than a verb+resource, so it falls short of the fully specific 5 tier, but an agent can still tell what it retrieves.

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?

There is no when-to-use guidance, no prerequisites, and no named alternative (e.g., a range or multi-day variant). 'For one date' hints at single-date scope but does not tell the agent when to pick this tool over anything else.

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