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

Annotations cover the safety profile (not read-only, not destructive, not idempotent), so the bar is lower. The description adds real behavioral value: it explains the scaling math, the automatic addition of perfumer's ethanol from the catalog when none is present, the strength cap, and that changes happen 'in place' — which corroborates the non-idempotent, in-place mutation hints.

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 usage trigger and stays compact, with no wasted sentences. The trailing fragments ('Capped at the concentrate's own strength. In place.') are terse but each carries information.

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?

No output schema exists, so the description must carry behavior, and it does so well for a mutation tool — mechanism, ethanol sourcing, and cap are all covered. The remaining gap is parameter semantics (units/meaning of totalGrams and concentrationPct), which is minor given the overall coverage.

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 only 33% (only 'formula' is documented). The description gives semantic context for concentration and finished weight, mapping loosely to concentrationPct and totalGrams, but adds no units, ranges, or format detail to compensate for the undocumented parameters. Baseline 3 for a partial-coverage schema.

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 and resource (change a formula's concentration or finished weight) and grounds it in the app's Scale sheet, with a concrete example (EDP to EDT). It is clearly distinguishable from siblings like update_formula or edit_formula.

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?

Opens with an explicit trigger ('Use this when the user wants to change...') and two distinct cases (concentration or finished weight). It stops short of naming when-not to use it or naming alternative tools, so no exclusions are given.

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