schema_field_exists

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

Annotations already declare readOnlyHint=true, so the read-only safety profile is provided. The description aligns with this annotation but adds no additional behavioral context (e.g., whether 'exists' means closed-world, error behavior, or usage limits). With annotations covering the main safety profile, a 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 a single sentence with no wasted words, front-loading the core action. It is appropriately sized for a simple tool.

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?

The tool is simple, both parameters are fully documented, an output schema exists, and annotations cover the read-only nature. The description lacks usage guidelines but is otherwise sufficient for an agent to invoke the tool correctly. Minor gap in not stating when to use it.

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 input schema documents both parameters with 100% coverage and includes concrete examples. The description adds no extra parameter semantics beyond what the schema already provides, so the baseline of 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?

The description states a specific action ('check if a field exists') and a clear resource ('entity schema'), making the tool's purpose unambiguous. No sibling tools are listed, so differentiation is not required. A small deduction for not specifying what the check returns, though the output schema presumably covers that.

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?

No guidance is provided on when to use this tool versus alternatives, nor any exclusions or prerequisites. The description only states what the tool does, not when it should be selected, leaving the agent to infer appropriateness from the name alone.

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