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. The description adds the concrete endpoint path and a security instruction to treat message text as untrusted customer content, which is genuine behavioral context beyond the annotations, though the warning reads as generic boilerplate for a group record rather than specific to this resource.

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?

Four short fragments, front-loaded with the action and resource, with no filler. "Read-only" duplicates the readOnlyHint annotation and is the only sentence that does not earn its place.

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 single-parameter read with full annotation coverage this is close to sufficient, but with no output schema the description never indicates what a group record contains (name, contact count, etc.), leaving the agent to discover the return shape empirically.

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 0% and the schema only constrains id to a positive integer with no name or meaning. The description partially compensates by showing the id as the {id} path segment of /v2/group/{id}, implying it is the group identifier, but it adds no format or sourcing guidance.

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 ("Read one contact group") plus the underlying endpoint GET /v2/group/{id}, which pins down exactly what is fetched. The singular "one" implicitly distinguishes it from smsglobal_list_groups and smsglobal_list_group_contacts, but no sibling is named explicitly.

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: "one contact group" signals a single-record fetch rather than a listing, so an agent can infer it should use this when it already has a group id. There is no explicit statement of when to prefer it over list_groups or list_group_contacts, and no prerequisites noted.

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