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

Annotations already declare a safe, idempotent, read-only operation, so the bar is lower; the description still adds real behavioural information by disclosing that photon rate for optical power, photons per joule, momentum, and overlapping ISO 21348 spectral categories are all computed and returned. It does not state what happens for invalid input or how multiple spectrum matches are ranked, which is the remaining gap.

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 dense sentences, front-loaded with the conversion scope before listing derived outputs. No filler, though the second sentence packs several distinct output types together rather than structuring them as a short list.

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 carries the return-value burden and does so by enumerating derived outputs (photon rate, photons per joule, momentum, ISO 21348 categories). Combined with the annotated safety profile and documented parameters, an agent has enough to call it correctly; only error behaviour and output units are unstated.

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 67% and both required parameters are already documented, so the baseline is 3. The description does add meaning for power_w by tying it to the 'photon rate for optical power' output, but the unit enum members and their semantics are left entirely to the schema.

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?

"Convert vacuum wavelength, frequency, spectroscopic wavenumber and photon energy" gives a specific verb plus an enumerated set of quantity families, and names the constant set (CODATA 2018). It is clearly distinct from neighbourhood tools like photon_attenuation or bragg_peak, though the boundary against convert_radiation_units is left implicit.

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?

Usage is only implied: the list of accepted quantity families signals that this is the tool for photon-energy/wavelength/frequency interconversion. There is no explicit statement of when to prefer it over convert_radiation_units, nor any prerequisite or exclusion mentioned.

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