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

Annotations already declare that this is a non-read-only, non-destructive, idempotent, closed-world operation. The description adds useful context about what registration enables (server reminders) and why the tool exists outside the normal self-registration flow.

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 two tightly written sentences with the core action and usage context front-loaded. There is no redundant or filler text.

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 simple three-parameter registration tool with annotations covering safety and idempotency, the description is mostly complete for selection and basic invocation. The main remaining gap is parameter-level guidance for token, platform, and label.

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%, so the description should compensate for three undocumented parameters. It mentions the device token conceptually but does not explain token format/minLength, the platform enum, or the optional label parameter.

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: "Register a device token," and explains its purpose in terms of server reminders. It also distinguishes the normal phone-app self-registration path from the testing/manual use case.

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?

It clearly says when this tool is intended: testing or manual token registration, compared with the phone app registering itself. It does not explicitly mention alternatives such as list_devices or delete_device, but the main usage context is clear.

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