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

Annotations only declare readOnlyHint=false, so the description carries the burden and does it well: it discloses that tracking is ON by default, that force_reader replaces the body with a stub and routes the recipient through mosadd's secure reader, that auto_destruct expires the reader link, and that watermark surfaces in screenshots/prints. These are non-obvious side effects an agent must know before calling.

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 purpose and sending identity, then grouped into recipients, body, and monitoring/legal options. The telegraphic parenthetical style is efficient, though the semicolon-chained clause on tracking is dense enough to risk misreading on a fast scan.

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 12-parameter mutation tool with no output schema, it covers the fields that have surprising behavior and leaves plain fields to the schema. It omits failure modes and any note on sender provisioning, which would be useful but are secondary.

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 already 83%, and the description still adds genuine meaning: it explains the runtime consequence of force_reader (stub + secure reader + print/copy/time-on-read observability), the true/string polymorphism of watermark, and the legal rationale for disclose_tracking. It leaves the delivery limits on to/cc/bcc to the schema, so 4 rather than 5.

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 and resource ('Send an email') and pins the sending identity to the user's own mosadd address, which implicitly separates it from mAYL_send_as_agent and from mDM_send/sms_send channels. It does not explicitly name the alternatives it is not, so it stops short of a 5.

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 real usage guidance for the body fields ('Pass body_text or body_html (or both)') and for the compliance options ('default on; set false for no tracking', 'recommended for GDPR/ePrivacy compliance'), but says nothing about when to choose this tool over sms_send, mDM_send, or mAYL_send_as_agent. Tool-selection guidance 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.