get_emails_content

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

The description goes beyond the readOnlyHint=false annotation by explaining exactly why the tool is non-read-only: 'because mark_as_read=true changes remote flags.' This discloses a conditional side-effect and clarifies the default behavior (read-only unless mark_as_read is true), providing valuable context that the annotation alone does not convey.

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 exactly two sentences: the first states the core function, the second adds a usage directive and a transparency note. Every sentence earns its place, with no wasted words, making it highly concise and well-structured.

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 description covers the essential context: what it retrieves, the prerequisite call, and the side-effect behavior. With an output schema present, return values need no explanation. However, it does not explicitly state the max number of emails or that email_ids can be an array, but those details are in the schema. Minor gap in missing explicit mention of multi-email support, but overall adequate.

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 100%, and parameter descriptions already explain meaning, defaults, and paging behavior (e.g., body_offset, max_body_length, and the truncation marker). The tool description adds no additional parameter semantics beyond what the schema provides, so the baseline 3 is appropriate.

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 a specific verb+resource: 'Get the full content (including body and reply-thread headers) of one or more emails by their email_id.' It distinguishes this from sibling tools like list_emails_metadata, which presumably returns metadata only, making the tool's unique role obvious.

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 explicitly instructs to 'Use list_emails_metadata first,' providing a clear prerequisite and implying that list_emails_metadata is for metadata only. However, it does not explicitly state when not to use this tool or compare it to other alternatives like download_attachment, so it misses the full 'when-not/alternatives' guidance needed for a 5.

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