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

With no annotations, the description carries the full burden of behavioral disclosure. It explicitly disclaims credential granting and approval skipping, and correctly scopes the side effect to labeling the client_id used with device_start. This prevents an agent from assuming the tool performs authorization.

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 sentences deliver purpose, usage timing, and explicit non-effects with no filler. The most important outcome is front-loaded, and the limitation is stated at the end without undermining the core message.

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 single-parameter tool with no output schema, the description is complete: it explains when to call it, what it changes, what it deliberately does not change, and how it relates to the adjacent device_start flow. Nothing essential is missing for correct invocation.

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 100%, so the baseline is 3. The description adds cross-tool context by connecting client_name to the client_id used in device_start, but it does not add meaningful detail about the parameter's format, constraints, or behavior beyond what the schema already states.

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 names a specific action ('Register this MCP client'), cites the relevant standard (RFC 7591), and states the practical effect: the client name appears on the device_start approval screen. It clearly distinguishes the tool from device_start and register_webhook_target by explaining what registration does for the approval flow.

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 gives explicit timing ('call this once before device_start on first setup'), states that it is optional but recommended, and clarifies what it does NOT do ('Does NOT grant any credential or skip human approval'). This tells an agent exactly when and why to invoke it.

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