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

Goes well beyond the readOnly/idempotent annotations: discloses the 6-item cap, that products are counted at the most per-day amount each label suggests, that country=GB switches to NHS guidance, how hidden amounts and fish-oil EPA/DHA are handled, and what totals/other_totals/items/not_found contain. Rich operational detail an agent needs.

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?

Front-loads the purpose and the outcome in the first two sentences, then adds examples and interval/return detail. It is dense but nearly every sentence carries unique information; only minor tightening (semicolon restatement) is possible.

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 output schema, the description carries the return contract itself, enumerating totals, other_totals, items, and not_found plus the upper-limit comparison logic. An agent has everything needed to call and interpret this tool correctly.

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 coverage is 100%, so baseline is 3, but the description adds real semantics: a hard 'up to 6 items' limit and the interpretation rule that each product is counted at its maximum per-day label amount. The semicolon format is echoed from the schema rather than added.

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?

States a specific verb+resource: it adds up everything a user takes and checks daily totals against adult upper limits. The scope (aggregate multi-item checking) clearly distinguishes it from siblings like supplementcheck_check_dose and supplementcheck_get_nutrient.

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?

Provides two concrete trigger examples ('I take Centrum, vitamin D 5000 IU and zinc 50 mg, is that too much?' and the OLLY Sleep melatonin case) that make the intended use obvious. It does not explicitly name or exclude the sibling dose-checking tool, so it stops short of full when/when-not guidance.

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