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

Annotations already establish readOnlyHint=true, so safety is covered. The description adds genuine context beyond that: results are limited to groups the caller 'can see' (visibility/permission scoping) and member counts are flagged as slower, a performance caveat. It doesn't cover pagination behavior, so not a 5.

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, zero filler, with the resource and returned fields front-loaded and the optional behavior trailing. Every clause earns 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?

With no output schema, the description usefully names the returned fields, and annotations plus a fully documented schema cover safety and parameters. It is nearly complete for a simple read-only list tool, though it says nothing about ordering or total-count/pagination behavior.

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 100%, so the schema already documents page, max_results, and include_contact_counts (including the 'slower' note). The description's 'optionally with member counts' merely restates the boolean without adding syntax or default details, so the 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?

States a specific verb+resource ('List the contact groups') and even enumerates the returned fields (GroupId, Name, Sharing, Color), so the agent knows exactly what comes back. It doesn't explicitly distinguish itself from siblings like lacrm_list_contacts_in_group or lacrm_get_contact_groups, which would have pushed it to 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?

The phrase 'optionally with member counts' implies when to enable that flag, and 'you can see' hints at a permission scope, but there is no explicit when-to-use/when-not guidance and no sibling is named as an alternative. Usage is only implied.

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