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

With no annotations, the description carries the burden and does disclose a key failure mode: mismatched nuclei return status "error" with nucleus_mismatch, nucleus_a and nucleus_b instead of a bogus score, plus the default matching window of 0.05 ppm. It omits auth/api_key requirements, what happens on unreadable paths, and whether any state is written.

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 paragraphs, output capabilities front-loaded, error semantics second. No filler and nothing repeated from the name.

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 needn't be explained, and the comparison semantics are well covered. But for a 6-parameter tool with 0% schema coverage, leaving api_key, solvent, and the nucleus override unexplained is a real gap an agent could trip on.

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% across 6 parameters, so the description must compensate. It only clarifies tolerance_ppm (default 0.05) and indirectly nucleus (each file declares its own), leaving path_a, path_b, api_key, and solvent undocumented — notably raising the question of what the `nucleus` parameter does if files already declare one.

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+resource ("Compare two NMR spectra") and enumerates the outputs produced: matched peaks, correlation, RMS shift difference, similarity verdict. An agent can tell this apart from covnmr_analyze, covnmr_verify, or covnmr_identify without opening any schema.

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 a concrete intended use ("e.g. batch against reference") and specifies the invariant that both files must share a nucleus, which effectively rules out cross-nucleus comparisons. It doesn't explicitly name sibling alternatives such as covnmr_verify or covnmr_analyze, so the routing guidance is contextual rather than explicit.

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