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

Annotations already cover the safety profile (not read-only, not destructive, not idempotent, closed world). The description adds real context beyond them: a newly created field does not render in signatures until it is placed into a template, which is a non-obvious consequence an agent would otherwise miss.

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 short sentences with zero waste. The core purpose is front-loaded and the non-obvious lifecycle caveat follows immediately.

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 annotations and full schema coverage plus no output schema, the description is nearly complete. The one gap is that it never says what comes back (e.g., the new field's identifier), which an agent likely needs to place the field into a template — the very follow-up step the description raises.

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% and the enum descriptions for source and data_kind are unusually rich (including the UNMANAGED/MANUAL default behavior). The description adds nothing about parameters, so baseline 3 applies.

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?

States a specific verb and resource: 'Add a custom field to the workspace registry.' The create verb clearly separates it from update_smart_field, delete_smart_field, and list_smart_fields, though it never names those siblings explicitly.

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?

Usage is implied by 'Add a custom field to the workspace registry,' but there is no explicit when/when-not guidance, no mention of prerequisites, and no routing to update_smart_field for existing fields. The second sentence hints at lifecycle but not at tool selection.

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