water_today

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

No annotations are supplied, so the description carries the full burden. It does disclose useful behavior: this is a detail/read listing (明细), it returns four specific data groups, and it requires app version 3.8+, which is a real compatibility constraint. It stops short of stating side-effect freedom, auth needs, or empty-state behavior, which leaves gaps for an unannotated tool.

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 compact sentence with the resource and scope front-loaded, then the returned fields. The parenthetical version requirement is placed where it is immediately visible. Nothing is padded, though the colon-separated field list reads slightly dense.

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?

With no parameters and no output schema, the description's enumeration of return contents (total, goal, quick cup sizes, per-record entries) does the job the missing output schema would otherwise do. The version prerequisite covers the main environmental risk. Only the relationship to today_summary remains unaddressed.

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 tool takes zero parameters, so there is no parameter meaning to add; the baseline for a parameterless tool applies. The schema and description are consistent in presenting a no-argument call.

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 names a specific resource and time scope ('今天的喝水明细' – today's water log details) and enumerates what is returned: total, goal, quick cup sizes, and individual records. It is clearly a read of today's water data, distinguishable from the write sibling log_water. It does not, however, explicitly contrast itself with today_summary, which likely also surfaces water totals.

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?

Usage is only implied: 'today' signals the temporal scope, and the mention of app 3.8+ hints at an environment prerequisite. There is no statement of when to prefer this over today_summary or how it complements log_water. An agent can infer it is the per-record read path, but nothing is spelled out.

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