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

Beyond the read-only annotations, the description adds the monitoring:read auth requirement, newest-first ordering, the domain-filtering behavior, the returned fields, and the scoring_version interpretation. It also tells the agent to render report_url as a clickable link, which is useful operational context not covered by the annotations.

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 front-loaded with the usage trigger and then moves efficiently into auth, ordering, and follow-up behavior. It is somewhat over-detailed in enumerating returned fields despite having an output schema, but the field list and report_url instruction are not wasteful enough to undermine the structure.

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 list tool with annotations and an output schema, the description covers the missing contextual pieces: when to use it, required auth, filtering and ordering, and the related get_email_test call. An agent has enough information to invoke it and interpret the result correctly.

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 input schema already has 100% description coverage for both limit and domain, so the schema carries the parameter semantics. The description restates the optional organization-level domain filtering but adds no syntax or edge-case detail beyond the schema. Baseline 3 is appropriate when structured fields do the heavy lifting.

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 uses a specific verb and resource: it lists the account's email tests, newest first, with an optional domain filter. It explicitly distinguishes itself from get_email_test, which retrieves the full result for a single test. An agent can select it against the sibling retrieval tools 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?

It gives an explicit triggering condition: a signed-in user asking about prior email tests or how a sender's earlier tests scored. It also states the required API token scope and names get_email_test as the follow-up when a specific test_id is needed. This is clear when-to-use and alternative guidance.

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