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

Annotations already tell the agent this is a non-idempotent write that is not destructive. The description adds one genuinely useful behavioral fact - the material is drawn from the source bottle's stock - but says nothing about whether the source stock is actually decremented, what happens on repeat calls, or what is returned.

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 tight sentence that leads with the triggering condition, with no padding or redundancy. It is well-formed, though it could have spent its length budget on parameter meaning instead.

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 mutation with zero schema coverage and no output schema, the description is far too thin. An agent can infer the intent but cannot confidently fill the required targetPct/grams pair or the source-vs-dilution fields from what is written here.

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 0% across 7 parameters, so the description carries the full burden and largely fails it. It only gestures at 'source bottle's stock' and never explains targetPct, grams, solvent, material, fromDilutionPct, or the deductFromSource flag, leaving most inputs ambiguous.

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 the action (recording a dilution) and the source (a bottle the user owns, with material taken from that bottle's stock), so the intent is clear. It stops short of distinguishing this from the sibling scale_to_concentration, which plausibly overlaps, so it doesn't reach 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?

It gives a concrete trigger: use when the user has made, or wants to record, a dilution from a bottle they own. That is real usage guidance rather than a restatement of the name, but it names no alternatives or exclusions against the many sibling tool names.

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