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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description adds real value by mapping the tool to 'POST /api/crm with Action list', which pre-empts confusion about a POST-backed tool that is actually a read, and by enumerating the fields returned. It stops short of describing paging behavior or result-size implications, which the schema carries instead.

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 compact sentences: the returned-field inventory comes first, the REST mapping second. No filler and nothing redundant with the annotations.

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 parameterless read-list tool with full schema coverage and clear annotations, the description supplies enough: what it lists, what each entry contains, and the underlying API action. The returned-field list partly substitutes for the missing output schema; only pagination semantics are left entirely to the schema.

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% and the schema already documents limit (default 500, max 1000) and offset (with the next_offset paging hint). The description adds nothing about parameters, so the baseline 3 applies even though the endpoint/action note gives useful framing.

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 ('List the stored lists (CRM groups) of mobile numbers') and adds the returned fields (CrmId, description, number count). The plural 'lists' with no id parameter clearly separates it from the sibling get_contact_list, so an agent can pick correctly without opening the 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?

Usage is implied by the listing semantics and the returned field set, but the description never states when to use this versus smseveryone_get_contact_list, nor any conditions or exclusions. The REST endpoint reference ('POST /api/crm with Action list') is implementation detail rather than routing guidance.

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