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

Annotations already indicate readOnlyHint=false, so the description is not required to restate that it's a write. However, the description adds minimal behavioral context beyond the name: it only adds the COMPANY-type constraint. It does not disclose whether this replaces existing employees, whether it can be called multiple times, or what the response structure implies. Given the presence of annotations, a 3 is fair; it adds a little but not rich context.

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 a single sentence with no redundant words. It front-loads the core action and the key constraint. It is appropriately sized given that the schema carries the parameter details.

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 mutation tool with 10 parameters and many similar sibling tools, the description is too sparse. It does not mention prerequisites (e.g., subject must exist and be a company), whether it is an additive operation (likely), or how it relates to smi_add_subject_employer. While an output schema exists, the description fails to guide an agent on when to choose this tool over others or what side effects occur. This is a significant gap for a complex mutation.

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 all 10 parameters have detailed descriptions in the schema (e.g., subjectId references prior calls, isCurrent asks to clarify with user). The tool description itself adds no parameter-level information. Baseline for high coverage is 3, and the description does not need to compensate.

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 action (attaches an employee), the resource (SMI subject), and a key scope constraint (COMPANY-type subjects). This distinguishes it from sibling add-tools (address, alias, phone, etc.) which target different entity types. The verb 'attaches' is specific and not a tautology of the name.

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 usage by mentioning COMPANY-type subjects, which hints at when to use it, but it does not explicitly state alternatives or exclusions. For example, it does not differentiate from smi_add_subject_employer (which likely handles the reverse relationship) or explain when not to use this tool. The context is present but not fully explicit.

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