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 behavioral value by disclosing the shape of the returned payload (HTML and plain text content, recipient groups/searches/segments, links, schedule, status) in the absence of an output schema. It does not mention auth needs or the effect of the include_* flags, keeping it below 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?

A single dense sentence with the main payload facets front-loaded and zero redundant restatement of the name or title. Every clause names a distinct returned data category.

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 single-record getter with a fully documented three-parameter schema and no output schema, the description sufficiently conveys what comes back that an agent could not infer from structured fields. A brief note on the optional include_* flags would make it fully complete.

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%, including a helpful pointer that mailing_id comes from emma_list_mailings, so the schema carries the parameter burden. The description adds nothing about the include_segment_names / include_subscription_names flags, only implying segment data is returned; 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 and resource ('Get one mailing in full') and enumerates the returned facets (content, recipients, links, schedule, status), which clearly separates it from the list-style siblings and from the narrower emma_list_mailing_links / emma_get_mailing_response tools. It stops short of explicitly naming a sibling it is not, so it is clear but not fully differentiated.

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 'Get one mailing in full' — an agent can infer this is the detail-view counterpart to emma_list_mailings. However, there is no explicit when-to-use/when-not-to-use guidance or routing to alternatives like emma_get_mailing_response for stats.

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