directus_list_fields

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

With no annotations provided, the description bears full responsibility for behavioral disclosure. It states 'List' implying a read-only operation, but provides no information about pagination, rate limits, error behaviors, or what data structure is returned (even generally).

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 appropriately concise with a single sentence containing zero fluff, though the '[UNIFIED]' prefix appears to be implementation metadata that adds no value for agent decision-making.

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 zero schema descriptions and no annotations, the description is insufficient. It lacks documentation for the required `site` parameter, provides no output schema hints (even though one exists in context), and omits behavioral constraints necessary for safe invocation.

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 0%, requiring the description to compensate. While it explains the `collection` parameter's purpose (optional filtering), it completely fails to document the required `site` parameter, leaving critical semantic information (what constitutes a valid site identifier) undefined.

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 core action (List) and resource (fields), and specifies the optional filtering capability. However, it does not explicitly distinguish this tool from siblings like `directus_get_field` (single field retrieval) or clarify what constitutes a 'field' in the Directus context.

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 collection' implies when to use the filter parameter, but provides no explicit guidance on when to choose this listing tool versus `directus_get_field` for specific field lookups, nor does it mention prerequisites like permissions or the `site` parameter requirements.

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