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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered by structured data. The description adds genuine value beyond that by disclosing the payload contents (delivery statistics) and the underlying endpoint, but says nothing about error behavior or cost of the outbound call implied by openWorldHint.

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 short sentences, front-loaded with the outcome and backed by the endpoint mapping. Nothing is padded, though the raw REST path is of marginal value to an agent that cannot call URLs directly.

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-only fetch with no output schema, the description is close to sufficient: it names the resource, the lookup key, and the non-obvious return content (delivery statistics). The remaining gap is that the shape of those statistics is unknown and there is no mention of not-found handling.

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 0% and the single required group_id has no schema description, so the description must carry the burden. 'By id' does confirm group_id is an identifier and that exactly one result is expected, but it does not restate the integer/positive constraint beyond the schema or explain where a group id is obtained (e.g. from list_transactional_groups).

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 resource and scope: a single transactional group retrieved by id, plus the payload it returns (delivery statistics). This implicitly distinguishes it from the sibling vision6_list_transactional_groups, which returns many. The verb is elided into a noun phrase ('One transactional group by id'), so the action is inferred rather than stated, but it remains unambiguous.

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?

The phrase 'by id' implies this is the retrieval path when the caller already holds a group id, and the plural sibling makes the alternative inferrable, but the description never names vision6_list_transactional_groups or states when to prefer it. No prerequisites, no guidance on what happens with an invalid or unknown id.

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