get_number

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

No annotations exist, so the description bears full burden. It only states 'Get details' without disclosing behaviors like read-only operation, authentication needs, or what happens if the number is inactive. For a retrieval tool, more transparency is expected (e.g., latest response format, error states).

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, terse sentence with zero unnecessary words. It efficiently conveys the tool's purpose without redundancy or overload.

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?

The tool is simple (1 param, no output schema), but the description does not specify what 'details' are returned, which could confuse an agent. Since there is no output schema, more information would enhance completeness. However, for a basic retrieval, it is minimally viable.

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% for the one parameter, and the description adds no additional meaning beyond the schema's 'Phone number to retrieve'. According to the rule, baseline is 3 when coverage is high, so this is adequate.

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 'Get details of a specific active phone number' clearly specifies a verb ('Get'), resource ('phone number details'), and scope ('specific active'), distinguishing it from siblings like get_active_numbers which lists numbers. No ambiguity.

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 implies use for retrieving details of one number, but provides no explicit guidance on when to use versus alternatives (e.g., get_active_numbers for listing, get_contact for contacts). The sibling names provide context, but the description itself lacks explicit when-to-use or when-not-to-use instructions.

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