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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, so the description is consistent and adds context: the return format (base64, count, digest) and the recommendation to use getEmail first. There is no contradiction. The description does not mention rate limits or authentication needs, but the safety profile is covered by 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 two sentences: first states purpose and outcome, second gives usage guidance. It is front-loaded, concise, and every sentence adds value. No unnecessary words.

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?

Given the moderate complexity and the presence of an output schema (mentioned in context), the description adequately covers the return values (base64 archive, count, SHA-256 digest) and the workflow hint. No missing critical details for a read-only download 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?

Schema coverage is 100% (both parameters documented), so baseline is 3. The description adds value by explaining that the token parameter is optional and that the bearer token is used when omitted. It also advises on workflow (check attachment manifest first), indirectly guiding parameter usage. No additional parameter constraints are needed.

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 clearly states the tool downloads all attachments from an inbound email and returns a gzip-compressed tar archive as a base64-encoded string with count and SHA-256 digest. It specifies the resource (inbound email attachments) and action (download), distinguishing it from siblings like getEmail by advising to check the attachment manifest first.

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 explicit guidance: 'Prefer getEmail first to check the attachment manifest before downloading.' This recommends a workflow and implies when not to use this tool directly. The optional token parameter is also explained. However, it does not explicitly state when not to use it or list alternative tools for other scenarios.

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