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

Annotations already declare readOnlyHint/idempotentHint/openWorldHint=false, and the description usefully reinforces this with 'Static and offline', which confirms results are deterministic and safe to repeat. It adds real behavioral context (no network, cached reference data) beyond the safety flags, though nothing about limits or output shape.

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?

Front-loaded with the core purpose, and the trailing 'omit topic for every table' clause is a useful default up front. The long topic enumeration is somewhat redundant with the enum but does convey the breadth of the vocabulary in one pass.

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 an output schema present, return-value explanation is not required, and the description covers scope, default behavior, and offline/static nature. An agent has enough to call it correctly; only a pointer to a concrete alternative tool is missing.

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% and the single enum param is fully documented there, so baseline is 3. The description enumerates the same topic values in prose (plus extras like LHCb magnet polarities that map under 'lhcb') and restates the omit-for-all default, adding little beyond 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?

States a specific verb (decode/list) and resource (the controlled vocabulary) and explains exactly what it contains for the cern_opendata tool family. It is clearly distinguishable from siblings like get_records or search_records, which consume this vocabulary rather than define it.

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?

Explains where this fits: it decodes the terms the other cern_opendata tools accept, so an agent knows to consult it before constructing queries. It also states the no-argument default ('omit topic for every table'). It stops short of naming a specific alternative tool to use instead, so not a 5.

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