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

Annotations already declare this is a non-read-only, non-destructive, closed-world write, so the safety profile is covered. The description adds the useful auth/scope context that creation happens in the authenticated caller's workspace, but says nothing about idempotency, slug collision behavior, or side effects. With annotations carrying the main burden, this is an adequate-but-thin 3.

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?

A single front-loaded sentence with no filler or redundancy. It is structurally clean, though its brevity reflects under-specification rather than genuine economy.

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?

An output schema exists, so return values need not be explained, but for a creation tool with three undocumented parameters the description omits uniqueness constraints, error/conflict behavior, and any hint of what a created API contains. The agent has the bare minimum needed to attempt the call and little else.

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 0% across 3 parameters, so the description is the only place parameter meaning could be added, and it mentions none of name, slug, or description. The schema does encode that name is required and slug has a strict pattern, but the description adds zero semantic value on top of it.

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 gives a specific verb and resource ('Create an API') and adds the scope 'in the authenticated caller workspace'. It is clearly distinguishable from siblings like api_get/api_list and from the other *_create tools (connection_create, endpoint_create, secret_create). It stops short of any explicit sibling routing, but the resource is unambiguous.

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?

There is no when-to-use, when-not-to-use, or alternative guidance. The agent is told the workspace context but nothing about prerequisites (e.g., whether the workspace must already exist, whether slug must be unique) or when another tool is more appropriate.

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