read_email

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

No annotations are present, so the description must carry the behavioral disclosure burden. It does disclose what the tool returns (From, To, CC, Subject, Date, Body, Attachments), which is useful. However, it does not mention whether reading an email has side effects (e.g., marking it as read), error behavior, or authentication requirements. The description is functional but not rich in behavioral context beyond the output structure.

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 a single, focused sentence followed by a concise list of returned fields. It is front-loaded with the core action and resource, and every word earns its place. No filler 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?

Given the tool's simplicity (one parameter, no output schema), the description adequately explains what the tool returns and how to get the required ID. It lacks an explicit statement about side effects or errors, but for a read operation with clear return fields, it is sufficiently complete. The presence of sibling tools like thread hints at potential richer alternatives, but this tool's scope is well-defined.

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?

The input schema already covers the only parameter (id) with a description that includes provenance ('get from list_emails or list_unread_emails'). The tool description merely repeats 'by message ID' without adding new semantic details. Since schema coverage is 100%, the description adds minimal value beyond the structured schema.

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 uses the specific verb 'Read' with the resource 'email content by message ID', clearly distinguishing it from siblings like list_emails (listing) and mark_read (changing state). It lists the exact fields returned, making the tool's purpose unmistakable.

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 implies usage context by stating 'by message ID' and the schema param description directs users to get the ID from list_emails or list_unread_emails. While it doesn't explicitly say 'use this instead of list_emails for full content', the workflow is clear enough. No exclusion or alternative guidance is given, but the context signals and param description provide adequate direction.

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