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

readOnlyHint=true already declares this a safe read, and the description is consistent with that. It adds what the response contains (line items, discount, tax) but says nothing about 404/not-found behavior, auth requirements, or rate limits, which is acceptable given annotation coverage but not rich.

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 compact sentence that leads with the purpose and tacks the REST endpoint on as a trailing reference. No filler; every clause 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?

For a simple read-by-id tool with no output schema, naming the returned components (line items, discount, tax) usefully compensates for the missing return schema. Only minor gaps in error/not-found behavior remain.

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?

Only one parameter and schema description coverage is 100%, so the schema fully documents order_id. The description adds no format, syntax, or sourcing detail beyond what the schema already states. Baseline 3 applies.

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?

Specific verb 'Fetch' plus resource 'a single order', with the payload scope spelled out (line items, discount, tax). 'Single' distinguishes it from the polar_list_orders sibling, so an agent can tell the two apart without opening schemas.

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 implied by the required order_id and the 'single order' framing, but the description neither names the alternative (polar_list_orders) nor states when to prefer this over it. No when-not or prerequisite guidance.

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