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

Annotations already cover readOnly/idempotent/non-destructive, but the description adds genuinely new behavior: submissions are persisted BEFORE the e-mail attempt, `delivered:false` + `error` semantics, that no visitor IP is stored, and that nothing is deleted. This is exactly the extra 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?

Front-loaded with the core verb+resource, then layers operational context in dense, purposeful sentences. It runs long, but nearly every clause conveys unique value; only minor tightening is possible.

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 read-only list tool with an output schema present, the description covers return shape (fields, delivered, error), scoping, and safety. The only gap is the undocumented `server` parameter, so it is not fully complete.

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 0%, so the description must compensate. It documents `days` (default 30, max 365) and `limit` (default 50, max 200) with constraints absent from the schema, but the `server` parameter is never explained, leaving one of three params dark.

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 (lists) and resource (contact-form submissions/leads) scoped to the user's hosted static site, distinguishing it from the many ad-platform lead tools (download_meta_leads, list_tiktok_lead_forms) in the sibling set. The 'every message the form relay received, whether or not the e-mail went out' clause sharpens the scope further.

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 clear situational context: it is the record behind configure_site_smtp and the place to look when a mail account refuses a send. It stops short of explicitly naming alternative lead-listing siblings (e.g. list_lead_form_submissions) or stating when NOT to use it.

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