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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds the mild nuance that the record must be addressed by the id used at creation and that the read is a simple GET, but nothing about permissions, rate limits, or what a missing id returns.

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?

Two brief sentences, front-loaded with the action and resource and with zero filler; the HTTP endpoint is a compact identifier rather than prose padding.

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 one-parameter read tool with no output schema and annotations that already declare safety, the description covers the essentials. It is nearly complete; only a pointer to when to prefer it over list_orders 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% for the single order_id parameter, so the schema already documents it. The description adds only the nuance that the id is the one from creation, which is marginal but real value beyond 'Order id.' — baseline 3 applies when the schema does the lifting.

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 (Get) and resource (one order record) plus the lookup key, which clearly separates it from the sibling mailbluster_list_orders. It does not explicitly name the alternative, so it falls short of 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?

Usage is implied rather than stated: fetching a single record by its id, and the phrase 'the id it was created with' hints the id must come from creation. There is no explicit when-to-use, when-not, or routing to siblings such as list_orders or update_order.

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