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

The readOnlyHint=true annotation already tells the agent this is a safe, non-mutating read, so the bar is lower. The description usefully adds what the response contains (including the latest import operation) but says nothing about auth requirements, rate limits, or error behavior for a missing/invalid list.

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?

One front-loaded sentence covering the payload, plus a short endpoint reference — no filler. The trailing 'Moosend: GET /lists/{MailingListID}/details.json' is mildly redundant but does anchor the operation for an agent.

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 compensates well by enumerating the returned fields. Both parameters are documented in the schema and the read-only nature is annotated, leaving only error/edge-case behavior unaddressed.

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% and both parameters are documented there, including that mailing_list_id is a GUID sourced from moosend_list_mailing_lists and that with_statistics defaults to true. The description adds no parameter-level meaning beyond the schema, so the baseline of 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 and resource ('Get one mailing list') and then enumerates the concrete payload (name, member counts, status, custom field definitions, preferences, latest import operation). The word 'one' implicitly separates it from the sibling moosend_list_mailing_lists, so an agent can tell the two apart without opening either 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?

The singular 'one mailing list' plus the required mailing_list_id imply this is the detail-fetch for a known list, but the description never states when to prefer it over moosend_list_mailing_lists or what happens if the ID is unknown. Usage is implied rather than guided.

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