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

With no annotations, the description carries the load well: it discloses the sender identity, that replies route to the user's own address, that the action is logged on the card, and the required permission — far beyond the name. It stops short of stating irreversibility/that a sent email cannot be recalled, or what happens on delivery failure, which matters for an external side-effecting action.

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?

Two sentences, front-loaded with the irreversible character of the action, then the operational constraints. No filler; every clause (sender, reply routing, permission, precondition) carries decision-relevant information.

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 no-annotation, no-output-schema mutation tool it covers the critical gating and permission context, but leaves the 'to' override behavior and post-send failure/reversibility semantics unspecified, which is the main remaining gap given only 25% schema coverage.

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 only 25% (only 'id' is described). The description says nothing about 'subject' and 'body', and critically nothing about the optional 'to' parameter — an agent cannot tell whether supplying 'to' overrides the lead's address, which is a high-risk ambiguity for a real send.

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 ('Sends a REAL email') and immediately qualifies the scope: it goes out from the CRM card with a 'via Vendo AI' sender and is logged on the card. The capitalized 'REAL' and the named prerequisite tool make it unambiguous versus the preview sibling.

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?

'Only call after the user approved the exact draft from crm_preview_email_to_lead' gives an explicit precondition and names the sibling that must precede it, so the agent knows both when to call and which tool to use first. The permission requirement (crm-contact-details) adds a further callable gate.

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