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

readOnlyHint=true already covers the safety profile, so the description only needs to add context. 'Full details' signals a complete record rather than a summary, which is mildly useful, but it says nothing about what happens on a missing/invalid resource name or whether the account parameter changes the result set.

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?

One short sentence with the resource and lookup key front-loaded and no padding. It is efficient, though the brevity leaves no room for the routing hint a caller would benefit from.

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 simple two-parameter read tool with full schema coverage and no output schema, so not much is required. The notable omission is the prerequisite identifier workflow, which an agent needs in order to know when this tool is actually callable.

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%, with both the account and resource_name parameters documented including an example format, so the schema does the heavy lifting. The description's phrase 'by their resource name' merely restates the required parameter and adds no new interpretation.

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?

Specific verb ('Get') plus resource ('full details of a specific contact') and the lookup key ('resource name'). It's clearly distinct from contacts_list and contacts_search in intent, but it never names those siblings or acknowledges that a resource name must first be discovered elsewhere.

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?

Usage is implied: call this once you already have a resource name. There is no explicit guidance on how to obtain that identifier (contacts_search / contacts_list) nor any statement about when to prefer this over those tools, so the agent must infer the workflow.

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