fetch_email_content

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the return structure ('Returns {id, subject, from, to, date, body, attachments}') and clarifies the limitation of attachment data ('metadata only'). However, it doesn't mention potential error conditions, rate limits, or authentication requirements that would be helpful for a read operation.

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 efficiently structured in three sentences: purpose statement, return value specification with important limitation, and usage guidance. Every sentence earns its place by providing essential information without redundancy. It's appropriately sized and front-loaded with the core functionality.

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 operation with no annotations and no output schema, the description does well by specifying the return structure and attachment data limitation. However, it could benefit from mentioning error handling (e.g., what happens with invalid IDs) or performance characteristics. The guidance on sibling tool relationships is strong, making it mostly complete for this context.

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%, so the schema already documents both parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema. It mentions the 'id' parameter contextually but doesn't provide additional semantics about format or constraints. Baseline 3 is appropriate when the schema does the heavy lifting.

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 specific action ('fetch the full content'), resource ('a single email'), and key identifier ('by its id'). It distinguishes from sibling tools by specifying it's for retrieving content of individual emails rather than listing or managing them, and explicitly differentiates from fetch_email_attachment for attachment data.

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 on when to use this tool ('use an id obtained from any of the list_emails_* tools') and when to use an alternative ('use fetch_email_attachment to download actual attachment data'). It clearly establishes the prerequisite relationship with list_emails_* tools and the complementary relationship with fetch_email_attachment.

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