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

With no annotations, the description must fully disclose behavior, but it only states 'Weight of metal stock per profile' without explaining return units, whether qty multiplies the result, or which dimensions are required per profile. It does not mention that this is a pure calculation with no side effects, leaving room for misinterpretation about output semantics.

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, front-loaded sentence that efficiently states the tool's purpose and scope. It avoids fluff and organizes profiles and materials clearly, though it could be expanded to include parameter mapping without losing conciseness.

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 complex with 9 parameters and multiple profile-specific dimension requirements, but the description is too sparse to guide correct invocation. It does not explain the relationship between profile and parameters, nor the output format. An agent selecting this tool would likely struggle to know which dimensions to provide for a given profile.

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 description adds little beyond the schema's parameter descriptions. It lists profile names that already exist as enums, but does not clarify which parameters are needed for each profile (e.g., pipe needs od_mm and wall_mm, beam needs height_mm and web_mm). With 67% schema coverage, the description does not compensate for the missing qty, profile, and material descriptions.

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 calculates the weight of metal stock and enumerates the supported profiles and materials, which distinguishes it from sibling tools like lumber_weight_calculator or green_log_weight. It names specific resources (pipe, round bar, etc.) and the implied verb 'calculate' is unambiguous.

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 context: it is for metal stock weight per profile, which implies when to use it. However, it does not explicitly mention exclusions or alternatives (e.g., lumber_weight_calculator for wood), so it lacks explicit vs.-alternative routing. The context is sufficient for correct selection among siblings.

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