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

Discloses 'Opens browser login' which is a disruptive side effect not captured by annotations, and the quota note adds useful context. Annotations (openWorldHint, readOnlyHint) are supplemented, not contradicted.

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 concise sentences front-loaded with the primary action, followed by two key behavioral notes. No wasted words.

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?

Simple tool with no params or output schema; description covers purpose, OAuth method, browser interaction, and quota impact. Sufficient for an agent to invoke 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?

Zero parameters, schema coverage 100%, so no parameter explanation needed. Baseline for 0 params is 4.

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 'Authenticate existing subscriber via OAuth' – a specific verb, target, and method. Clearly distinguishes from sibling tools like get_account_status or check_connection by specifying it's the login 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?

Provides clear context: it's for authentication, and notes 'Does not count toward your monthly searches' which implies it's a separate action. But doesn't explicitly state when to use vs alternatives or when not to use, so not a 5.

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