Read Email

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

With no annotations at all, the description carries the full burden and it does disclose several traits: the lookup never scans messages, max_chars caps only the body, truncation is reported explicitly, and attachment contents are never returned. That is meaningful behavior beyond a bare read, but permissions, error cases, and whether the read marks messages as read are not addressed.

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?

Front-loaded with the capability, then the constraints in short declarative sentences. Nothing is padded, though the line breaks fragment what could be two tighter sentences.

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?

An output schema exists, so return values need not be explained, and the description adds the behavioral caveats that matter (truncation metadata, no attachment contents). The remaining gap is the unexplained account/mailbox parameters, which is modest but not trivial for a required-account 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 description coverage is 0% for 5 parameters, so the description must compensate. It explains message_id's format and source, max_chars' scope, and output_format's values, but leaves 'account' and 'mailbox' entirely undefined -- including the fact that mailbox defaults to INBOX. Useful but incomplete against a full-coverage gap.

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?

States a specific verb ('Read') with a precisely bounded payload: headers, plain-text body, and attachment metadata for one message. That scope implicitly separates it from siblings like get_email_source (raw source) and list_email_attachments, though no sibling is named.

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?

Gives a concrete precondition -- use the numeric message_id returned by search_emails, not the RFC Message-ID header -- which is real routing guidance. However it never says when to prefer this over get_email_source, get_email_thread, or forward_email, so alternative selection is left to inference.

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