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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety and idempotency profile is fully covered by structured data. The description adds only the field list, with no further behavioral context such as error surface or result limits; the 404/403 semantics live in the schema, not the description.

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, zero filler, and the core purpose is front-loaded ahead of the id-provenance hint. Every clause earns its place.

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?

With no output schema, the description usefully enumerates the returned fields (name, mobile, email, WhatsApp, social ids, status, custom fields) so the agent knows what it gets back. It does not describe field types or handling of absent values, which is a minor gap for a single-record get.

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 100%, so the baseline is 3, but the description adds non-schema value by naming the two upstream sources for contact_id (list_contacts, a lead's contact_id). It says nothing additional about agent_id beyond what the schema already documents.

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 ('Get one contact of an agent') and enumerates the returned fields, which implicitly distinguishes it from the singular/plural sibling list_contacts. An agent can tell this fetches exactly one contact rather than a collection without opening the schema.

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?

Explicitly tells the agent how to obtain the required contact_id ('from list_contacts or from a lead's contact_id'), which is real routing guidance to two sibling tools. It stops short of stating when NOT to use this tool (e.g. bulk retrieval) or any prerequisite beyond the id source.

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