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

Annotations declare readOnlyHint: false, idempotentHint: true, and destructiveHint: false. The description adds valuable context: it explains the distinction between permanent (config header) and session-only (token parameter) logins, and that the token is a JWT. It does not contradict annotations and provides behavioral details beyond the structured data, though it omits potential failure modes or side effects.

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 a single but dense sentence that front-loads the purpose and then lists usage options. It contains no fluff, but the semicolon-heavy structure makes it slightly harder to parse. Still, every piece of information is relevant and nothing is redundant.

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 tool with one optional parameter and no output schema, the description covers all essential usage scenarios: how to trigger the login link, how to use a token, and the recommended permanent configuration. It does not describe expected return values (e.g., success/failure messages), but given the absence of an output schema, this is not a critical gap.

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?

The schema provides only a bare 'token' string with no description. The description fully compensates by explaining the token's purpose (JWT for session login) and its relationship to the config-header approach. It also clarifies that the parameter is optional (when omitted, the link is provided). This adds meaning far beyond the schema.

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 clearly states the tool's purpose: to authenticate with MCP.AI for IDE agents. It specifies the action (log in, obtain token) and provides concrete usage methods, distinguishing it from vague alternatives. While siblings like 'connect' exist, the description's specificity about authentication and token handling makes its purpose unambiguous.

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 instructions on when to use the tool: call with no arguments to get a login link, or call with a token for session-only login. It also explains the preferred permanent config method. However, it does not explicitly contrast with sibling tools (e.g., 'connect') or state when not to use this tool, so it falls short of a 5.

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