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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds minor context by explaining what custom fields are and that the tool returns a schema/template, but it does not disclose any additional behavioral aspects such as default workspace resolution or error handling. With annotations carrying the burden, this is acceptable but not enriched.

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?

Two sentences, with the core action front-loaded and the second sentence providing helpful context. No filler or redundancy; every word contributes to understanding.

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 simple read-only tool with two optional parameters, an output schema, and safety annotations, the description covers the essential purpose. Default workspace behavior is already documented in the schema, so nothing critical is missing. It could mention the relationship to file-level custom fields, but that's a minor gap.

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 workspace_id and workspace_name have thorough descriptions, including the optionality and default-workspace behavior. The tool description adds nothing about parameters, so the baseline of 3 is appropriate since the schema does the heavy lifting.

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 uses a specific verb+resource: 'Get the custom fields schema/template defined for a workspace.' It clearly distinguishes itself from sibling tools like get_file_custom_fields by scoping to workspace-level definitions, and from set_file_custom_fields by being a read operation.

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 gives clear context by specifying the workspace scope, which implies usage for workspace-level schema retrieval. It does not explicitly state exclusions or name alternatives (e.g., 'for file-level custom fields, use get_file_custom_fields'), but the context is unambiguous enough for correct selection.

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