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

No annotations are supplied, so the description carries the full disclosure burden. It does communicate the pricing model baked into the calculation ($2.30–$3.60/scoop) and that UL safety overlap is evaluated, which is genuine behavioral context beyond the schema. However, it never states that this is a side-effect-free computation with no external lookups, nor what the response shape looks like (e.g., whether it returns a per-nutrient overlap table or a boolean verdict).

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 front-loaded sentence that leads with the verb and the cost figures, with zero filler or marketing padding. It is dense — three separate outputs compressed into one clause chain — but nothing is wasted and no sentence is redundant.

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 3-parameter, all-optional calculator with full schema coverage and no output schema, the description does the essential job of naming the three results an agent can expect. The main remaining gap is whether 'annual household cost' covers multivitamin spend as well as AG1, which matters because taking_multivitamin is an input. That ambiguity is minor but real.

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 every parameter is already documented with units and defaults in the schema, so the baseline is 3. The description adds nothing parameter-specific beyond restating the per-scoop price range that the 'plan' enum field already spells out per tier. The 'days_per_week' baseline for 'annual household cost' is never connected to how annualization works.

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 uses a specific verb ('Calculate') with three named outputs: per-scoop AG1 cost, annual household cost, and NIH UL safety overlap with multivitamins. That is far more concrete than the name alone and clearly marks this as a calculator rather than a lookup, which distinguishes it from siblings like lookup_supplement_evidence and search_healthstylz_articles. It stops short of explicitly naming a sibling it replaces or complements.

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: an agent can infer this is the tool for cost math or multivitamin safety-overlap questions. There is no statement of when to prefer it over lookup_supplement_evidence for nutrient/UL questions, nor any exclusion for users outside the US or for non-AG1 products. Adequate but leaves routing to inference.

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