Fields: add

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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the description's added value is its disclosure of defaults: display type inferred from database type, on-delete defaulting to CASCADE, and automatic user/file linking. It also states the return value (the new field's id), which matters since there is no output schema.

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?

Four tight sentences, each earning its place: purpose, the type requirement, the defaulting rules, and the return value. The most important constraint (always pass the database type) is front-loaded.

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 17-parameter mutation tool with no output schema, the description covers the highest-risk gaps: default behaviors, relationship requirements, and the return value. Remaining parameter detail is fully covered by the schema, so the definition is complete enough to invoke correctly.

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 coverage is 100%, so the baseline is 3, but the description adds real semantics beyond the schema: how display defaults from type, that relationship types need target, and that on-delete defaults to CASCADE. It does not clarify the many boolean flags (unique, indexed, searchable, multiple), but it meaningfully enriches the relationship-related parameters.

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 field to an entity') and immediately clarifies it as adding a column to an existing entity, which unambiguously distinguishes it from fields_update, fields_delete, and fields_list. An agent can select it without opening the schema.

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?

Gives concrete conditional guidance: always pass the database type, relationship types require the target entity's name. It does not name alternatives (e.g. fields_update) or state when not to use it, so it stops short of the top band, but the usage context is clear.

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