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

Annotations indicate idempotentHint=true)Skip, readOnlyHint=false, destructiveHint=false, and the description adds that it is not a read-only operation (it modifies authentication state). It further explains the behavior of different invocation modes (with token vs without) and the permanence of the config approach. It does not contradict annotations, and adds context about what the tool does (getting a link vs accepting a token) that is not fully captured by the schema.

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 moderately concise, with three ideas packed into one long sentence. It is front-loaded with the essential purpose and usage, but the middle part about config headers is slightly verbose almonds. It is structured logically from purpose to usage, but could be broken into shorter sentences for clarity. It earns a 4 for being informative without unnecessary fluff.

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?

Given the simplicity of the tool (one optional parameter, no output schema), the description is largely complete: it explains the two modes (permanent config vs session token) and the no-arg behavior. It might benefit from noting the URL to open or the format of the token, but given the low complexity, it covers the essential aspects. The description is sufficient for an agent to understand how to invoke it 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?

The input schema has only one parameter 'token' with no description, and schema description coverage is 0%. The description compensates by explaining that the token is a JWT to be pasted, and it distinguishes between passing it and not passing it. It adds meaning beyond the schema by clarifying the token's role and the alternative of calling with no args, which is not evident from the schema alone.

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 the user with MCP.AI, providing both a browser login option and a token-based session login. It distinguishes itself from sibling tools by being the only authentication tool in the list, and it mentions context (IDE agents like Cursor). The verb 'log in' and 'authenticate' are specific, and it clearly associates the tool with the resource (MCP.AI).

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 explicitly provides two usage scenarios: 1) adding a bearer token as a header for permanent config, and 2) pasting a token for session-only login with no args to get the link. It also mentions when not to use it implicitly (it's for authentication, not for other tasks), and it contrasts with the permanent config option. This gives clear when-to-use guidance.

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