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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description's added value is the return payload (contact, origin, status, notes, first message), which is useful since there is no output schema, but it says nothing about behavior when the id is invalid or about message truncation.

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?

A single eleven-word fragment with zero padding, and the scope marker 'One lead' is front-loaded. It is efficient but slightly telegraphic rather than a well-formed sentence.

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?

A one-parameter read tool with full schema coverage and annotations needs little more, and the description supplies the otherwise-missing return shape. Only the failure/empty case and the first-message semantics are left unaddressed.

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 100% and the leadId parameter already documents its provenance ('Id from list_leads'). The description adds nothing about the parameter, so the baseline of 3 applies.

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 fragment 'One lead: contact, origin, status, notes and the first message' makes the resource and single-vs-list scope clear, and enumerates what comes back. It lacks a verb ('retrieve') and doesn't distinguish it from read_lead_chat, which plausibly covers the same message content.

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?

No guidance on when to use this versus list_leads (browse) or read_lead_chat (conversation), even though those siblings create genuine ambiguity around the 'first message' field. The only hint is indirect, via the schema's 'Id from list_leads'.

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