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

No annotations are provided, so the description must carry the burden. It only covers basic purpose and auth configuration, but omits side effects (e.g., mark_as_read), return format, error handling, or network behavior. The schema mentions options like mark_as_read, but the description does not clarify the default behavior or consequences of using them.

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 three short sentences, front-loaded with the primary purpose. Every sentence adds useful context about credentials or account selection, with no fluff or redundancy.

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?

The tool is complex (4 params with nested objects), has no output schema, and no annotations. The description fails to explain return values, default behaviors (e.g., mark_as_read defaults to false), or error conditions. An agent would lack critical information about what to expect after invoking the tool.

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?

With 50% schema description coverage, the description should compensate for undocumented top-level parameters (filter, options). It only mentions 'account' and .env fallback, which are already in the schema's property descriptions. The phrase 'with filtering options' is vague and adds no specifics about how to use filter or options objects.

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 states 'Read emails from an inbox via IMAP with filtering options,' clearly identifying the action (read), resource (emails from an inbox), and method (IMAP). This distinguishes it from sibling tools like send_email, create_email_rule, or check_email_config.

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 provides useful context: 'If IMAP is configured in .env, no credentials needed' and 'Use "account" to pick a named account (work, personal, etc.).' It gives clear operational guidance, though it does not explicitly mention when not to use this tool or name alternatives as in some other tools.

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