send_email

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

No annotations are provided, so the description carries the full behavioral burden, and it says almost nothing: it does not disclose irreversibility, whether mail is actually dispatched or queued, permission requirements, or rate limits. The tag '[guarded by intentplane]' is opaque jargon that hints at a policy gate without explaining what it blocks or what happens when the guard rejects a call.

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?

It is short and front-loaded, which is good, but the second clause is an unexplained mechanism tag rather than information, so the description is under-specified rather than economical.

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 described, but for a side-effecting send operation with zero annotation coverage and 0% parameter documentation, the description leaves most of what an agent needs to call it safely unstated.

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 must compensate for three undocumented parameters and it does not. In particular 'to' is an array of strings with no format guidance (raw addresses, names, IDs) and there is no note on whether multiple recipients are allowed or how they are handled.

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 states a specific verb and resource ('Send an email'), which is unambiguous about what the tool does. The sibling tools (get_balance, read_inbox, send_money) are far enough apart that no explicit differentiation is required, though it never states that it does not read or draft mail.

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?

There is no guidance on when to use this tool versus alternatives, no mention of prerequisites (authentication, verified sender, recipient validity), and no indication that read_inbox is the counterpart for reading mail. The agent gets only the bare action and must infer everything else.

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