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

Annotations indicate readOnlyHint=false and idempotentHint=true, and the description appropriately discloses the mutation by describing config modification and session-only storage. It explains the browser login flow and token handling, adding context not in annotations. Minor gap: it doesn't explicitly state whether the server state is altered beyond the config header, but overall it is transparent.

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 efficient and logically structured. It leads with the core action, then presents the preferred method, followed by the alternative. Each sentence contributes value, though slightly verbose in explaining both flows; still, it remains concise enough.

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 single parameter, no output schema, and provided annotations, the description is complete. It covers both usage modes, the token's purpose, and the expected outcome (link vs session). No essential information is missing for correct tool invocation.

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?

Despite 0% schema description coverage, the description fully explains the only parameter 'token': it is a JWT used for session-only login, and that omitting it returns a login link. This adds substantial meaning beyond the bare schema, fully compensating for the lack of schema documentation.

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 by logging in and providing an access token. It specifies two distinct methods (permanent config header or session-only token) and differentiates from siblings like 'connect' by focusing on token acquisition and usage.

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 guidance: 'Best: add it to this server's config as a header' recommends the permanent method, while 'or use paste it here for a session-only login' explains the alternative. It also states when to call with a token ('after the user pastes') and when to call without ('to get the link'). These clear directives eliminate ambiguity.

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