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

Annotations provide idempotentHint=true, indicating calling with no args returns a link (non-mutating). The description adds context about permanent vs session-only tokens and the token payload, which is helpful. However, it doesn't disclose what happens after authentication (e.g., response format, whether it persists state), but the annotations already cover the key idempotency trait, so this is acceptable.

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 two sentences, front-loaded with the target audience and main action, then explains two usage paths. It's concise but slightly dense with parenthetical details; still, every part earns its place and it's easy to scan.

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?

The tool is simple with one optional parameter, and the description covers the auth flow fully: how to get token, permanent config, session pass, and no-args behavior. It lacks a return-value description but there's no output schema, and the context is 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?

Schema coverage is 0%, so the description must compensate. The description explains the 'token' parameter as an optional JWT for session-only login, but it doesn't detail the format or behavior when omitted beyond 'get the link'. This is sufficient for a single optional parameter, but it could be more explicit about the token's structure.

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 users for MCP.AI, providing login instructions and supporting both permanent (config header) and session-only (token) authentication. It distinguishes itself from siblings by focusing on the authentication flow for IDE agents, though it doesn't explicitly compare to the 'connect' sibling.

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 provides explicit usage guidance: it tells the agent to log in via browser, copy the token, and either add it to the server config for permanent access or pass it as a parameter for session-only login. It also gives the no-args option to get the link, covering all call variants clearly.

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