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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful context — the counts returned and the default exclusion of test/hidden groups — but says nothing about pagination limits beyond the schema or the return envelope. Adequate but not rich beyond structured data.

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 tightly written sentences: first the resource and what the payload contains, second the scoping default and override. Every clause earns its place, with zero redundancy against the schema.

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 read-only, paginated list tool with full schema documentation, this is nearly complete: purpose, content of results, and default scoping are all present. The only shortfall is that return shape and pagination behavior are not mentioned and no output schema exists to cover that gap.

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 every parameter (limit, start, group_types) is documented in the schema, including enum meanings and the next_start hint. The description restates the group_types default only, so the baseline 3 is correct — it adds no meaning beyond the schema.

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 member groups/audience lists) and adds the distinctive detail that results include active, opted-out and error member counts. This clearly separates it from siblings like emma_get_group (single group), emma_list_group_members (members within a group) and emma_get_member_groups (groups for one member).

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?

Explains the default behavior (normal groups only) and how group_types expands scope to test and hidden groups, which is real selection guidance. It stops short of naming sibling alternatives or stating when a caller should prefer emma_get_group or emma_list_group_members instead.

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