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

Annotations already declare readOnlyHint=true, but the description goes well beyond them: it discloses that the call is read-only against the fulfillment provider with no order placed, that Printify stores return a refusal (not an error worth retrying), and that variants must already be synced. These are non-obvious failure modes an agent could not infer from structured fields.

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-loaded with the core behavior in the first clause, and subsequent sentences all carry distinct, useful constraints. It runs long and ends with a stray artifact token ('[#a2bd48]') that adds no value, which keeps it out of the top band.

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 5-parameter read-only estimator with no output schema, the description covers purpose, preconditions, provider limits, and even the returned cost components. Nothing an agent needs in order to call it correctly or interpret a refusal is missing.

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 100%, so the baseline is 3, but the description adds real meaning: it names the three inputs to supply (store, recipient, variants + quantities), stresses that country_code AND address1 are both required because the platform rejects street-address-less requests, and introduces the out-of-schema constraint that variants must be pre-synced.

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 ('Estimate production + shipping + tax + total for an order') and immediately scopes it as non-creating ('WITHOUT creating it'). An agent can distinguish this from submit_order_to_fulfillment or add_order_item without opening any schema.

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?

Explicit when-to-use ('preview landed cost before placing an order') plus hard when-not guidance: Printify has no pre-order estimate, so it refuses — do not retry, and do not present a cross-provider comparison that silently omits Printify. This is exactly the alternative-routing an agent needs.

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