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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered elsewhere. The description adds the useful scoping detail that the result is the set of versions the server will answer for (i.e., valid query inputs), but says nothing about the list's size, ordering, or whether it is exhaustive or paginated.

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?

One front-loaded sentence with zero filler, correctly sized for a no-argument list tool. Nothing is buried or padded.

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?

For a trivial zero-parameter read tool with full annotation coverage and no output schema, this is close to sufficient. The only real gap is whether the returned set is complete and stable enough to be used as a validation list.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the phrase 'the server can answer for' is the only semantic nuance and it is genuinely informative about what the returned identifiers mean.

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?

Specific verb and resource: 'List all AILANG versions', scoped by 'the server can answer for', which signals these are the valid version identifiers for other queries. It is distinguishable from neighbors like changelog_for_version, though the description never states that relationship 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?

Usage is only implied: an agent can infer this is a discovery call to find valid version identifiers, but the description never says when to call it, nor that it should precede calls such as changelog_for_version or benchmarks_for_model. No exclusions or alternatives are named.

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