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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds nothing beyond that: it does not mention the default maxResults cap of 25, the degradation to lean results beyond the cap, or any pagination/ordering behavior — all of which live only in the schema.

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?

A single front-loaded sentence with no filler. It is efficient, though for a tool with seven filter parameters and several unusual semantics, the extreme brevity borders on under-specification rather than tight writing.

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?

The rich schema and existing annotations carry most of the burden, and no output schema exists so return values needn't be described. Still, for a catalog-listing tool with complex filtering semantics and adjacent sibling list tools, the description leaves the agent without any routing or behavior context.

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%, so the seven parameters (including the non-obvious match token semantics, latestPerMajor, and includeExperimental interactions) are fully documented in the schema. The description only restates the language filter, adding no meaning beyond structured data; baseline 3 applies.

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 ("List available compilers") and mentions the optional language filter, so the agent knows what the tool returns. It does not, however, distinguish itself from siblings list_languages or list_libraries, which an agent could plausibly confuse it with.

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?

The phrase "optionally filtered by language" implies one usage path but gives no guidance on when to reach for this tool versus list_languages/list_libraries/compile, nor when to use the advanced filters (match, latestPerMajor, lean) that the schema defines. No exclusions or prerequisites are stated.

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