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

Annotations declare a non-read-only, non-idempotent, closed-world write, and the description adds meaningful context beyond them: the default visibility is private and the result is a fictional identity with no legal or payment authority. It does not cover uniqueness handling for slug or what a duplicate creation attempt does, leaving a small gap.

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?

Three short sentences, front-loaded with the action, then the default, then the safety boundary. No filler; each clause contributes.

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 21-parameter creation tool with no output schema, the description covers purpose and identity/safety framing but leaves the parameter surface and creation-failure behavior largely unaddressed. Adequate to select the tool, thin for invoking it 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?

With 21 parameters and reported schema description coverage of only 10%, the description needs to carry parameter meaning, but it only names four loosely ('name, biography, style, briefs'). It says nothing about required display_name, the slug uniqueness rule, the origin enum restriction, or the account_token/header interaction, so it does not compensate for the coverage gap.

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?

Names a specific verb and resource (creates an original persona) and lists the content it holds (name, biography, style, briefs). It clearly differentiates itself from update_persona by being the creation path, though it never names that sibling explicitly.

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?

Sets a negative boundary ('never a verified natural person, legal identity or payment authority') and a default ('private by default'), which implies when the tool is appropriate. But it gives no positive when-to-use guidance or explicit routing against siblings like update_persona or create_agent_account (only the schema mentions the account_token dependency).

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