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

The description explains that with no args it returns a link, and with token it performs a session login. It does not explicitly state the behavior when called with a token (e.g., whether it validates or stores it), but the annotations (readOnlyHint false, idempotentHint true) align with the notion of a non-destructive authentication side effect. The permanent config alternative is described, but the tool's own behavior is somewhat implicit. Still, it provides useful context beyond the annotations.

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 bit long and mentions configuration details (adding header to server config) that are tangential to the tool itself. However, it's structured logically: first says what it does, then best practice, then how to call. It could be tightened but is not verbose.

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 authentication tool with no output schema, the description covers the workflow, arguments, and usage scenarios. It tells the agent exactly what to do: get the link, present it to the user, and then call with the token. This is complete for its context.

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 coverage is 0%, but the description thoroughly explains the token parameter: it's a JWT that the user pastes, and calling without it yields the auth link. This adds meaning that the schema lacks entirely.

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 explains the tool's purpose: authentication for MCP.AI in IDE agents. It specifies the exact flow (browser login, copy token, call with token or no args to get link) and distinguishes between permanent (config header) and session-based (token argument) usage. This is a specific, actionable purpose statement.

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 step-by-step instructions for both authentication modes: configuring an Authorization header for permanent connection, or calling the tool with a token for session-only login, or with no args to get the login link. Clearly states when to use which approach, which is excellent guidance.

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