mfp_get_water

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

Annotations already disclose readOnly, idempotent, and non-destructive behavior. The description adds valuable behavioral context beyond that: the value is always in millilitres regardless of the account's UI unit setting, and it cites the underlying endpoint field name as evidence. This is useful context not available from annotations or schema.

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 front-loaded with its purpose, and the millilitre clarification earns its place because it prevents unit confusion. The internal reference to 'python-myfitnesspal's _get_water' is mildly unnecessary for an AI agent but does not detract significantly from clarity.

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 simple single-parameter read-only getter, the description is complete: it specifies input format, default behavior, return shape, and unit semantics. The annotations cover safety, and the return description covers what the agent needs to interpret the result. Minor missing details like error behavior or zero-intake handling are not critical here.

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 only parameter, date, is already fully described in the schema with format and default behavior. The description repeats that information but adds no new semantic detail. Since the schema covers this parameter well, the baseline 3 is appropriate.

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 and resource ('Get water intake') and qualifies it with 'for a specific date', which distinguishes it from write operations like mfp_set_water. It is immediately clear what this tool does and how it differs 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?

The intended use is implied by 'Get water intake for a specific date' and the readOnlyHint annotation. However, it never explicitly names alternatives or gives when/when-not guidance, such as 'use mfp_set_water to log water' or 'use mfp_get_diary for broader daily data'.

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