getCustomField

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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only states the action without any detail on return format, error behavior, permissions, or side effects. For a mutation or complex tool this would be a serious gap; for a simple getter it is still minimal disclosure, hence a low score.

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 concise sentence that front-loads the verb and resource. No wasted words, and it is appropriately sized for a simple parameterless-except-id getter. It fits the tool's simplicity perfectly.

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 the single required parameter with full schema coverage and no nested objects or output schema, the description is adequate but has gaps. It never states what is returned (e.g., the custom field object) or how errors are handled (e.g., 404 if not found). With no annotations to fill in safety/behavior, the tool is not fully specified, but the simplicity keeps it at a minimum viable level.

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% since the only parameter 'id' has a description 'Custom field ID'. The description's 'by ID' confirms the schema but adds no new meaning. Baseline for high coverage is 3, and no extra semantic value is provided, so the score stays at baseline.

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 'Get a custom field by ID' uses a specific verb with a clear resource and the method of lookup. It unambiguously distinguishes this getter from related list/create/update custom field tools, even though it doesn't explicitly differentiate from getDealCustomField which operates on a different resource.

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 provides no guidance on when to use this tool versus alternatives like listCustomFields or getDealCustomField. There is no mention of prerequisite steps, typical use cases, or situations to prefer another tool. It is a bare statement with zero usage context.

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