read_email

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

readOnlyHint=true already signals a safe read, but the description adds value beyond the annotation by disclosing the return shape (headers, decoded body, attachment names, flags) and the truncation behavior via max_chars. Auth requirements and rate limits remain undisclosed.

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 one-sentence purpose covering both action and return, followed by a compact Args block with no filler. Every sentence carries information an agent needs.

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?

Complete for a single-message read: identity source, required param format, truncation knob, and return contents are all covered, and an output schema exists so return values need no further elaboration.

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%, so the description carries the burden, and it does: it explains that message_id must be the full Message-ID header including angle brackets, that folder locates the message, and that max_chars truncates longer bodies. Minor gap: no mention of the default values already present in the 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?

States a specific verb+resource (read one full message) plus scope ('one' vs the list/search siblings) and names where the Message-ID originates, which routes the agent away from list_emails/search_emails.

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?

Explicitly frames this as a follow-up to list_emails or search_emails, giving a clear usage context and an implied input source. It does not state when to prefer get_thread for conversation reading, so the exclusion is absent but the context is solid.

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