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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=false, so the mutation profile is covered. The description adds the auth scoping ('signed-in user') and clarifies that ingredient amounts are per-dose, but it does not warn that non-idempotent calls can create duplicates, nor whether adding a supplement auto-creates schedule entries.

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?

One sentence, front-loaded with the action and resource, with zero filler. It is efficient, though the brevity borders on under-specification relative to the 10-parameter surface.

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 non-idempotent mutation with 10 parameters, 10% schema coverage and no output schema, the description leaves too much open: duplicate handling, whether the supplement becomes active/scheduled, and the meaning of most optional fields are all unstated.

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 10% across 10 parameters, so the description must compensate and does not. It clarifies only the ingredients array ('per dose'), leaving form, brand, currency, dosageUnit, productUrl, defaultDosage, dosesPerPackage and pricePerPackage undocumented in both schema and description.

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?

A specific verb ('Add') plus resource ('supplement product') plus scope ('signed-in user's Stackwell stack'), with the ingredients-per-dose payload named. It is clearly distinguishable from stackwell_update_supplement or stackwell_set_supplement_ingredients by the word 'Add', though it never names those siblings.

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 creating a brand-new stack entry. There is no guidance on what to do when the supplement already exists (update vs. set_ingredients vs. create), and no stated prerequisites such as having an active plan.

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