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

The description discloses the tool's behavior: it returns a link when no token is provided, and accepts a token for session login. It also explains that the config method is permanent and non-expiring. Annotations indicate idempotentHint: true, which aligns with the tool's nature; the description adds context about security (token) and session vs permanent, which is not in annotations. However, it doesn't mention potential side effects like invalidating prior sessions, but that's a minor gap.

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 concise and front-loaded with the tool's purpose, then explains usage. It's a single paragraph but well-structured with clear instructions. It could be slightly more structured (e.g., bullet points) 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?

The tool is simple with one optional parameter and no output schema, so the description covers the essential aspects: login flow, token usage, and permanent vs session. It doesn't explain return format, but that's not critical for an authentication tool. It sufficiently covers context 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?

Parameter 'token' is not described in the schema (0% coverage), but the description explains its meaning: a JWT copied from browser after login. It distinguishes when to pass it vs. not, adding significant value beyond the schema. The description effectively compensates for the lack of schema descriptions.

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 via browser and obtaining an access token. It distinguishes between two modes: permanent config-based login and session-only token pasting. This is specific and differentiates from siblings like 'connect' and 'show_version'.

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 scenarios: when to use the permanent config method (recommended) vs. session-only login, and explains how to call the tool (with no args to get the link, or with a token). It also mentions best practice (adding header to config), giving 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.