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

The annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the bar is lower. The description adds genuine non-annotation context — deprecation status and behavioural equivalence to start_device_login — but says nothing about the authorization parameter, auth requirements, or failure behavior.

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 deprecation warning is correctly front-loaded, but the sentence 'use start_device_login. Deprecated — use start_device_login (same behaviour)' restates the same instruction twice across the description and title, which is wasted space rather than concision.

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?

An output schema exists so return values need not be described, and the essential routing decision (don't use this, use start_device_login) is present. However, the undocumented authorization parameter and the absence of any statement on whether the tool still works leave gaps for an agent deciding to invoke it.

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% and the single parameter 'authorization' is entirely undocumented in both schema and description. With one unexplained parameter the description should compensate, and it does not.

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 never states what the tool actually does — it only declares deprecation and points at a replacement. The phrase 'same behaviour' implicitly ties it to start_device_login, but a sibling named start_account_registration is left unaddressed, so the agent gets routing information without a clear statement of the resource/action.

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?

'DEPRECATED: use start_device_login' is an explicit when-not-use directive with a named alternative, which is exactly the guidance an agent needs. It falls short of 5 because it doesn't say whether the tool still functions or when a legacy caller might legitimately need it.

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