devices

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds context about the maximum number of linked devices (4), which is useful beyond the input schema. However, it does not cover other behavioral aspects such as error handling, response format, or performance characteristics (e.g., rate limits), leaving gaps that lower the score to 3.

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 extremely concise and front-loaded, consisting of only two sentences that directly convey the tool's function and a key constraint. Every sentence earns its place without redundancy or unnecessary elaboration, making it highly efficient and well-structured.

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?

Given the tool's low complexity (1 parameter, no output schema, no annotations), the description is somewhat complete but has gaps. It explains what the tool returns and a constraint, but lacks details on output format, error cases, or integration with sibling tools. For a simple query tool, this is adequate but not fully comprehensive, warranting a score of 3.

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 input schema has 100% description coverage, providing detailed documentation for the single parameter (phone). The description adds no additional parameter semantics beyond what the schema already explains (e.g., it does not clarify parameter interactions or usage nuances). According to the rules, with high schema coverage (>80%), the baseline is 3, which is appropriate here.

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 purpose: 'Returns the number of linked devices.' It specifies the verb ('returns') and resource ('linked devices'), making the action explicit. However, it does not distinguish this tool from its siblings (e.g., base64_encoded_profile, business_insights), which limits it to a 4 instead of a 5.

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 provides no guidance on when to use this tool versus alternatives. It mentions a constraint ('Max number of linked devices is 4') but does not explain when this tool is appropriate compared to sibling tools like privacy_settings or status, nor does it specify prerequisites or exclusions. This lack of contextual usage information results in a score of 2.

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