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

Annotations already declare this as a read-only, idempotent, non-destructive operation, so the safety profile is covered. The description adds two pieces of value beyond them: result ordering (newest first) and the required read_crm scope. It says nothing about pagination behavior or result shape, so it clears the lowered bar but doesn't exceed it.

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, resource and ordering front-loaded, auth requirement appended. Nothing is wasted or buried.

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 paginated list tool with no output schema, the description should say something about cursor-based paging and what a reply record contains. The auth scope is a helpful addition, but the pagination and result-shape gaps keep it at minimum viable.

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 coverage is 75% and the descriptions that exist (since, cursor, contact_id) are self-explanatory; only limit is undocumented. Since the description adds no parameter meaning at all, the baseline 3 for high schema coverage 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?

The description names the resource (replies from contacts) and the ordering (newest first), which is enough to understand the operation. It falls short of a full verb+scope statement and never distinguishes this from nearby tools such as get_thread or list_email_status.

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?

No guidance on when to use this versus siblings like get_thread or list_email_status; the only conditional statement is an auth requirement, which is not usage guidance.

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