get_project_fields

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds only a hint about the nature of returned data (required status and available values) but no additional behavioral traits such as authentication or rate limits. Since annotations carry the burden, a baseline of 3 is appropriate.

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 compact and front-loaded: the main purpose is in the first sentence, followed by usage guidance and parameter explanations. No wasted words, and each section earns its place.

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?

Given the tool's simplicity, the presence of an output schema, and annotations covering safety, the description provides everything needed to call it correctly: what it does, when to use it, and what the parameters mean. Nothing essential 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 schema has 0% description coverage, but the description explicitly explains both parameters: 'project' as a project short name and 'instance' as an optional YouTrack instance. This compensates well for the missing schema descriptions, though it could add format or default details.

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 clearly states the tool lists custom fields for a project, specifies the resource (custom fields) and includes what is returned (required status and available values). It effectively distinguishes this from sibling tools like create_issue by positioning it as a discovery tool.

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?

Explicitly instructs to use this before create_issue to discover required fields and valid values, giving clear contextual timing. It does not mention when not to use it or alternatives, but the primary use case is well defined.

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