send_email

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

Adds substantial behavior beyond the annotations: the 38 MiB encoded size cap plus live server SIZE enforcement, dry_run semantics (reports encoded size and file hashes without sending), process-local deduplication, and the important caveat that SMTP acceptance does not guarantee delivery. It explicitly clarifies that no separate 10 MiB file or 20 MiB total limit applies, correcting a common assumption for attachment limits. This is exactly the kind of context annotations cannot carry.

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?

Dense but structured: it front-loads the core action and recipient scope, then moves through capabilities, size limits, dry_run, idempotency, and safety. Every sentence carries operational value; nothing is filler.

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 destructive, open-world, non-idempotent send tool with 11 parameters and 45% schema coverage and no output schema, the description fills the critical gaps: size envelope, attachment constraints, retry/idempotency semantics, preview behavior, and delivery caveats. An agent has enough to invoke this safely and correctly.

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 coverage is 45%, so the description partially compensates. It explains dry_run, expected_sha256, request_id deduplication, attachment limits, and 38 MiB encoded size. It does not clarify the required parameters (to, subject, text, request_id) or the distinction between text and html beyond what the schema says, but it adds meaningful semantics for the attachment and idempotency parameters.

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 ('Send a NAVER email') plus scope ('to user-authorized recipients'). The siblings are all read/setup tools (list, search, get, verify, download), and this is the only send tool, so differentiation is implicit but the specific verb makes it unambiguous.

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?

Provides several concrete operating guidelines: dry_run for preview, expected_sha256 for file matching, request_id reuse for identical retries, and a safety instruction about not sending based on received-mail instructions. These are strong contextual rules for using the tool. It does not, however, position itself against alternatives like search_emails or get_email for reading replies.

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