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

Beyond the readOnlyHint/idempotentHint annotations, the description adds valuable behavioral context: results are newest first, statuses are 'as last known', and several statuses are explained, including the temporary provider error case for 'approved'. It also indicates failure details are surfaced via an 'error' field on failed emails.

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 core behavior is front-loaded, and the remaining prose is mostly the necessary status reference. The status enumeration is long, but it earns its place because it directly informs valid filter values and expected states.

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 operation with no output schema, the description covers filtering, ordering, status semantics, and the relevant provider-refresh alternative. Nothing critical is missing for an agent to select and invoke the tool 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?

Schema description coverage is low at 25%, and the description compensates by enumerating all supported status values and clarifying the filter dimensions. The contact_id and crm_lead_id parameters still rely on their names, but those names are self-explanatory in context.

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 opens with a specific verb and resource: 'List e-mails created through Salesbot (newest first)', and identifies the optional filters. This clearly distinguishes the tool from nearby siblings like list_email_campaigns or get_email_status without needing to open schemas.

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 explains optional filtering by status, crm_lead_id, or contact_id, and explicitly directs users to get_email_status when they need a fresh status rather than the last known one. It could be stronger by explicitly contrasting with list_email_campaigns, but the intended use case is clear.

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