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

The description discloses the tool's behavior for all three invocation paths, including side effects: it returns a login link when called with no args, completes login when given a token, and warns that tokens are non-expiring when used in config. While annotations declare idempotentHint=true, the description doesn't contradict this and adds context about session persistence and the recommended permanent setup.

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?

Concise and information-dense. Every sentence serves a distinct purpose: context for the target audience, recommended permanent approach, temporary fallback, and argument handling. The parenthetical about MCP.AI for IDE agents is short but crucial for understanding why this tool exists, and the forward-reference to config setup is well-placed.

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?

For a tool with 1 optional parameter and no output schema, the description is complete: it covers all invocation modes, provides security context (non-expiring tokens), and explicit usage alternatives. The example of the token format is a nice touch. No additional information would meaningfully improve the agent's ability to use 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?

Schema coverage is 0%, but the description thoroughly explains the single token parameter's purpose and format: 'call with { token: "<jwt>" }'. It makes clear the parameter is optional and what happens when omitted. The description fully compensates for the lack of schema descriptions, though it doesn't specify validation rules like token format validation.

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 with a specific verb+resource combination: 'log in in the browser, copy the access token' and describes the three ways it can be invoked. It distinguishes itself as an authentication helper for the server, clearly separated from sibling tools like 'connect' and 'marketplace' by its focus on JWT-based session management.

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 instructions on when and how to use the tool, including the recommended alternative: 'Best: add it to this server's config as a header `Authorization: Bearer <token>`. It also clarifies fallback usage for session-only login and no-arg invocation, covering all parameter combinations.

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