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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context by detailing the rollup contents and ordering ('domains needing attention (lowest score / open alerts first)'), which goes beyond the annotations. No contradictions.

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?

The description is two sentences and front-loaded with the main verb and scope. The first sentence is a slightly long but well-structured list, and the second sentence gives usage. It is concise and free of jargon or fluff.

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 thoroughly enumerates all the important return values (average score, grade distribution, alerts, attention list, client breakdown), making the output fully understandable. Input is trivially complete with zero parameters. Sibling context confirms its portfolio-level role.

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?

The tool has zero parameters, so there is no schema to clarify. According to the rubric, a baseline of 4 is appropriate for zero-parameter tools, and the description correctly avoids inventing parameter details.

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?

The description clearly states the tool provides an org-wide deliverability rollup across all monitored domains, enumerating specific metrics like average score, grade distribution, alerts, and client-group breakdown. This distinguishes it from sibling getters like get_deliverability_score or get_domain, which focus on individual domains.

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 description explicitly says 'Use this for an at-a-glance portfolio health summary across an agency or multi-domain account,' giving clear usage context. However, it does not explicitly name alternatives or specify when not to use it, so it stops short of a 5.

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