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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the meaningful physics caveat that results are narrow-beam (no buildup factor) and sourced from NIST XCOM, but does not say what quantity is returned (μ, μ/ρ, or transmission fraction), which matters for a calculation tool.

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?

Two short sentences, zero filler, with the core identification front-loaded and the unit reminder placed second. Nothing is wasted.

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 simple read-only calculation with fully described parameters, the definition covers inputs well. However, with no output schema, the description should say what the result represents (attenuation coefficient vs. transmitted intensity), and it does not — a real gap for a computational tool.

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%, so all three parameters are documented in the schema itself. The description's 'thickness in mm and energy in keV' merely restates what the schema already says, adding no new semantics such as accepted material ID formats or energy range limits. Baseline 3 is appropriate.

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 names a specific physical quantity (narrow-beam photon attenuation) and the authoritative source (NIST XCOM), which clearly distinguishes it from siblings like energy_loss or material_properties. It stops short of a full verb phrase describing the computed output, but the resource and method are 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?

It states unit conventions for inputs but gives no guidance on when to choose this tool over energy_loss or material_properties, and no prerequisites or exclusions. An agent must infer applicability (shielding/attenuation calculations) from the tool name alone.

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