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

With no annotations, the description carries the full burden and does so excellently: it reveals the one-time-only API key return, and the exact header/env-var names for using the key in remote vs. local contexts. This is precisely the kind of critical operational behavior an agent needs.

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 tight sentences: the first defines the operation and parameter semantics, the second delivers an irreplaceable warning about one-time key return and usage. No wasted words.

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?

Since an output schema exists, the description needn't detail return values, but it still flags the crucial one-time nature of the API key. The only missing context is guidance on when this tool is appropriate relative to other account-related actions, which are absent from the sibling list anyway.

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 0%, so the description must compensate. It clarifies that owner_email is optional and that its presence or absence changes the account type ('user' vs 'guest'), adding significant meaning beyond the bare schema. Handle remains undocumented, preventing a full 5.

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?

Specific verb (create) and resource (agent account), and it goes further by explaining the semantic consequence of the optional owner_email parameter. No sibling tool in the list competes with this purpose.

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 implies this is the entry point for obtaining credentials, and the owner_email explanation gives conditional behavior. However, it doesn't explicitly state when to use this vs. other onboarding paths or any prerequisites.

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