List DataLens Trino resource presets

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

Annotations already declare readOnly, idempotent and openWorld, so the safety profile is covered. The description adds genuinely non-obvious context beyond that: the tool is experimental and unmeasured, and an unknown environment returns 403 Permission denied rather than 404, which materially changes how an agent should interpret failures.

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?

It is short and front-loads the resource definition, but the second sentence is densely and awkwardly phrased ('An environment nothing knows answers 403 Permission denied, not 404') and takes a re-read to parse. The ideas earn their place; the phrasing does not fully earn the space it takes.

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 read-only, auto-paginated list with 100% schema coverage and no output schema, the description supplies the one thing structured fields cannot: what the listed items represent and the non-standard error semantics. It stops short of describing returned fields, but the safety and schema layers cover most of the remaining burden.

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% – both limit (with its configured-cap default) and cloud_environment_id are already documented in the schema, including the auto-pagination cap. The description adds no parameter-specific syntax or semantics, so the 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?

The description defines exactly what the resource is – 'the sizes a cluster's machines may have in a cloud environment' – which is more informative than restating the title, and the tool name carries the 'list' verb. It does not distinguish this from the near-identical sibling datalens_sparkclusters_resource_presets_list or the singular resource_preset_get, so it never reaches a 5.

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?

There is no explicit when-to-use guidance and no mention of the obvious alternatives (the singular preset getter, or the Spark variant of the same list). The closest thing to routing guidance is the 403 error note, which is about failure behavior rather than tool selection.

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