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

Annotations already establish this as a read-only, non-destructive, closed-world calculation. The description adds useful domain context—balanced equations and an optional limiting-reagent mode—but does not explain error behavior for unbalanced equations or how the different input combinations interact.

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 a single front-loaded sentence with no filler. It communicates the core operation and the optional mode efficiently.

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 7-parameter tool with a nested object and multiple input modes, the description is adequate but leaves gaps. It does not clarify how find, given_moles vs. given_mass, and given_formula/target_formula combine in the non-limiting path; the output schema and annotations cover the return and safety aspects.

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%, so the parameter descriptions already carry the main burden. The description only adds that the amounts parameter triggers an optional limiting-reactant mode, which is useful but marginal beyond the schema's own explanation.

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 computational operation and resource: mole/mass stoichiometry for a balanced equation, with optional limiting-reactant mode. It is clear what the tool does, but it does not explicitly distinguish itself from nearby siblings such as calculator_moles or calculator_molar_mass, so it falls short of a 5.

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 implied by the need for a balanced equation and the optional limiting-reactant path via amounts. However, there is no explicit guidance on when to choose this tool over related calculators like calculator_moles or calculator_concentration, and no when-not-to-use conditions.

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