vunit_export_json

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

Annotations only declare readOnlyHint=true and openWorldHint=false. The description goes beyond this by revealing non-obvious behavior: the export is cached at .vunit-mcp-cache/export.json and re-run only when project sources change. It also discloses that no simulator is required. These are meaningful behavioral traits not captured in the annotations.

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?

Three short sentences, each earning its place: purpose and contents, attribute meaning, and caching/no-simulator behavior. There is no redundancy, fluff, or repetition of what the schema or annotations already convey.

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 zero-parameter, read-only export tool with an output schema, the description is complete. It tells the agent what is exported, that the result is cached and when it is refreshed, and that no simulator is required. Nothing an agent needs to correctly invoke this 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?

The tool has zero parameters, so the description carries no parameter semantics burden. Schema coverage is trivially complete. The baseline for a 0-parameter tool is 4, and the description appropriately omits parameter information that would be irrelevant.

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 opens with a specific verb and resource: 'Export the project model (source files, all tests, attributes) as JSON.' It enumerates what is included, mentions the exact CLI flag (--export-json), and even notes that attributes carry requirement/traceability data. This clearly distinguishes it from siblings like vunit_list_tests or vunit_list_files, which only cover subsets.

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 description provides useful context such as 'Does not require a simulator' and the caching re-run condition, which helps an agent understand when the tool is feasible. However, it never explicitly tells the agent when to choose this tool over alternatives like vunit_list_tests or vunit_list_files, nor names them. The usage guidance is implied rather than stated.

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