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

With no annotations, the description carries the full burden. It discloses the two computational paths and the parameter counts that trigger each, which is useful, but says nothing about the required api_key parameter, error behavior when fewer than 2 mode inputs are supplied, or that this is a deterministic read-only computation.

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 short lines, front-loaded with the purpose and then the two modes. Every sentence earns its place and the label structure (Mode 1 / Mode 2) makes it easy to scan.

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?

An output schema exists, so return values need not be described. However, for an 8-parameter tool with two distinct operating modes, zero schema descriptions, and no annotations, the description leaves real gaps: api_key need, path_length, mw, and the standards JSON format are all undocumented.

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 0%, so the description must compensate for all 8 parameters. It names absorbance, epsilon, concentration, standards, and unknown_absorbance, but leaves mw, path_length, and api_key entirely unexplained, and gives no units or format for the 'standards JSON' string.

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 action (quantification) and the two underlying methods (Beer-Lambert law, calibration curve) plus the inputs each requires. An agent can distinguish it from the analytical siblings like covauv_auto_analyze or covauv_predict, though the description never names those siblings explicitly.

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 clear context for selecting between Mode 1 (supply 2 of absorbance/epsilon/concentration) and Mode 2 (standards JSON + unknown_absorbance), which is exactly the decision an agent must make. It does not, however, state when to pick this tool over sibling tools such as covauv_auto_analyze or covauv_validate.

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