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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real value: it discloses the sort order (newest first) and that message bodies are excluded from results. It stops short of covering pagination behavior or how large result sets are bounded.

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 short sentences with no filler; the read mode and the most decision-relevant constraint (bodies omitted) are front-loaded. Every clause conveys information the agent cannot get elsewhere.

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 four-parameter, paginated list tool with no output schema, the description covers result shape partially (bodies excluded, newest first) but leaves pagination defaults and the account-scoping filter unexplained. Adequate to call the tool, not adequate to call it well.

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 0%, so the description carries the full burden, yet it only documents one of four parameters — and even for email_campaign_status it lists legal values without saying the parameter filters by that status. page, per_page, and email_account_id get no mention at all.

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 names the resource (E-mail campaigns) and the mode ([read]), and states two concrete output traits: bodies are omitted and rows come newest first. It does not distinguish this list tool from siblings like get_email_campaign or list_email_campaign_recipients, so an agent must infer the boundary from the names alone.

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?

There is no explicit when-to-use statement, no exclusions, and no named alternative. The parenthetical '(bodies left out)' hints that a different tool is needed for full content, but the agent is left to guess that get_email_campaign is that tool.

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