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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, closed-world write, so the safety profile is covered. The description adds real behavioral context — the source bottle's strength drives source and solvent grams, and a target stronger than the source is invalid — but says nothing about what happens to the source bottle itself or failure modes beyond that one constraint.

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?

Three sentences, front-loaded with the triggering condition and followed by the key disambiguation and the core numeric constraint. No filler, though the middle sentence could absorb the constraint more tightly.

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 seven-parameter mutation tool with low schema coverage and no output schema, the description identifies the tool's role and one hard constraint but omits what solvent/material select, how fromBottle/fromDilutionPct interact, and what the call yields. Adequate to select the tool, thin for invoking it confidently.

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 only 29%, so the description carries real weight here, and it does explain the targetPct/source-strength relationship that constrains the required inputs. However, five parameters (material, solvent, fromBottle, fromDilutionPct, targetPct) have no schema descriptions, and the description leaves their meaning and units largely to inference.

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 states a specific action and resource: recording a dilution made from a bottle the user owns, which produces a new stock bottle drawing on the source bottle's stock. It explicitly separates this from a formula concentration change, though it does not name the sibling tool (e.g., scale_to_concentration) that handles that case.

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?

It gives a clear triggering condition ('when the user has made, or wants to record, a dilution from a bottle they own') and an explicit exclusion ('not a formula concentration change'). It does not name the alternative tool an agent should pick for the excluded case, but the context is unambiguous.

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