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

Annotations already declare readOnly, idempotent, closed-world behavior, so the safety profile is covered elsewhere. The description adds real value by naming the physics basis (CODATA 2018, classical radiation formulae) and clarifying that the result is beam radiation rather than facility electrical demand, but it says nothing about output units or validity ranges for the computed quantities.

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?

Three dense sentences: outputs first, then required inputs and the either-or constraint, then modeling assumptions and scope. No filler, and the most decision-relevant content is front-loaded.

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?

With no output schema, the description does the work of naming the returned quantities (loss per turn, radiated power per beam, critical photon energy, optional revolution frequency), which is what an agent needs to pick this tool. It omits the units of those returned values, the one remaining gap for a physics calculator with no output schema.

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 83%, so the schema already documents nearly every parameter including the radius/field mutual exclusion. The description reinforces the either-or constraint and adds one genuinely new detail — that optional circumference yields revolution frequency — which is not in the schema. Otherwise it largely restates structured fields.

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?

States a specific verb ('Calculate') plus the exact quantities produced: dipole synchrotron energy loss per turn, radiated power per beam, and critical photon energy, scoped to an isomagnetic ring. It separates itself from facility-level tools ('beam radiation rather than facility electrical demand') but never explicitly distinguishes itself from the sibling energy_loss.

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?

Gives concrete invocation conditions: supply total beam energy including rest energy, beam current, and exactly one of bending radius or dipole field. It stops short of naming alternatives (e.g. energy_loss) or stating exclusions, so the agent must infer which tool wins when both could apply.

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