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 substantial behavioral context by enumerating what the preview returns (nodes, elements, springs, load cases, combination counts, check locations, earth-pressure basis, derived geometry) and clarifying that no model is required. It does not describe failure behavior or validation-error output, which keeps it from a 5.

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?

The description is front-loaded with the core purpose and then packs the return contents densely. It is a long sentence, but every clause appears to carry useful information and there is no obvious filler.

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 no output schema and only one optional parameter, the description carries most of the explanatory burden and does so by listing the returned artifacts. Combined with read-only annotations, this is nearly complete, though it could clarify the exact response shape or validation-failure behavior.

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 nested project parameter is fully documented in the schema, including default merging and array replacement semantics. The description adds no meaning beyond the schema for the parameter, so the baseline of 3 is appropriate.

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 states a specific verb and resource: it validates a 2D Culvert project using the plugin's Eurocode core and returns the generated model data. This clearly distinguishes it as a preview/dry-run tool, though it does not explicitly name sibling tools like culvert_build or culvert_analyse_and_check.

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 'Needs no model' implies this is a pre-build validation step, which gives implied usage guidance. However, the description never states when to use this versus culvert_build, culvert_analyse_and_check, or culvert_report, nor does it explicitly exclude use cases.

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