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

Annotations indicate idempotent and non-destructive behavior. The description adds context about the two modes (session vs permanent) and explains how the token is used. It does not contradict annotations and provides supplementary behavioral details beyond what annotations state, though it doesn't describe consequences of invalid tokens or detailed state changes.

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 long but highly informative, packed with specific instructions and structured into 'Best' and 'Or' alternatives. It front-loads the main purpose and provides actionable steps without wasteful filler, earning a score above average, though slightly 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?

The description covers the complete authentication flow: how to get the link, how to use a token for session login, and how to set up a permanent header. It does not mention the return value (e.g., the link itself), but since there is no output schema, it's not strictly required. The guidance is sufficient for an agent to know exactly how to invoke this tool.

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 only defines a single 'token' string without detailed description (0% coverage). The description clarifies that 'token' is a JWT from the browser login, used in the call with '{ token: "<jwt>" }', adding meaning beyond the bare schema. It does not elaborate on format constraints or validation, but the basic semantics are well explained.

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 identifies the tool's purpose: handling authentication for MCP.AI by logging in via browser, obtaining a token, and supporting both permanent and session-based setup. It specifies the resource (authentication) and differentiates from unrelated sibling tools by focusing solely on the auth workflow.

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 on when and how to use the tool: call with no arguments to get the login link, call with a token for session login, and recommends the permanent header configuration as the best practice. This clearly states usage scenarios and alternatives, though it doesn't mention when not to use it relative to siblings, the scope is clear.

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