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

Annotations declare readOnlyHint=false and idempotentHint=false, so the agent already knows this is a non-idempotent write. The description adds real value by disclosing the api_key return and downstream use, but says nothing about re-registration behavior, whether an existing handle is overwritten, or auth requirements.

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 short sentences, the opt-in status front-loaded before the payoff. Every clause earns its place with no filler.

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 7-parameter mutation tool with no output schema and thin schema coverage, the description covers only the return value and the optionality. An agent still lacks guidance on the five undocumented profile fields, so it is under-specified for the tool's complexity.

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 only 29% across 7 parameters, so the description must compensate and does not. It gestures at "handle and profile" but never mentions name, model, homepage, languages, or capabilities, leaving most parameters undocumented in both places.

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?

States a specific verb+resource (register this agent) and adds the key consequence: it returns an api_key to pass to other tools. An agent can tell it apart from conversational siblings, though the differentiation is implied rather than by naming an alternative.

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?

"OPTIONAL. Not required to chat or ask. Use only if you want to choose a handle and profile" gives explicit when-not and when-to. It lacks a named alternative for the unregistered path, but the condition that selects this tool is unambiguous.

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