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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows it's a safe read operation. The description adds behavioral context by stating there is 'only' one contact channel, which implies the tool returns a single result without multiple options or filtering. This is useful beyond the annotations.

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?

The description is two sentences, front-loaded with the core action. The first sentence states what the tool does, the second gives the usage context. There is no redundancy or filler; every word 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?

For a zero-parameter, read-only tool with no output schema, the description provides sufficient context: what it returns and when to use it. It doesn't specify the exact format of the contact channel (email, phone), but the title 'Get contact details' implies that, and the tool's simplicity makes this adequate. The annotations cover safety, so no further behavioral detail is necessary.

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?

The tool has zero parameters, so the description bears no responsibility for parameter explanation. According to the rubric, a baseline of 4 applies for 0-parameter tools. The schema coverage is vacuously 100%, and the description correctly implies no input is needed.

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 description clearly states the tool's function: 'Return the only contact channel for ARCLERA DIGITAL, LLC.' This is a specific verb ('return') with a specific resource (contact channel) and entity scope (ARCLERA DIGITAL, LLC). It also differentiates from sibling tools by focusing on contact, whereas get_company and get_services cover other aspects.

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?

The description gives clear usage context: 'Relevant when a user asks how to reach Arclera.' This tells the agent when to invoke the tool. It doesn't explicitly mention alternatives or exclusions, but the sibling context and the specificity of 'how to reach' are sufficient for a simple tool.

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