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

Annotations already indicate idempotence (idempotentHint: true) and non-destructiveness (destructiveHint: false), while the description adds behavioral context about persistence: it explains the difference between a permanent header-based connection and a session-only login, and mentions that calling with no args returns a link. This goes beyond the annotations and clarifies the tool's side effects and usage modes.

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 a single sentence but packs significant information: context, best practice, alternative, and parameter usage. It is front-loaded with the purpose and remains under 100 words. While slightly dense, it is concise and well-structured.

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 simple tool with one optional parameter and no output schema, the description covers the primary workflows (header config vs. session token vs. link retrieval). It doesn't describe edge cases like error handling or token expiration, but these are less critical for an authentication helper. The description is complete enough for an agent 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?

The input schema has 0% description coverage (no param descriptions), but the tool description compensates by explaining the 'token' parameter: it should be a JWT string and is used when pasted for session-based login. It also implies the parameter is optional since calling with no args is an alternative. This adds meaningful semantic context for the single parameter.

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: authenticate the user by logging in and obtaining an access token. It explicitly mentions 'log in in the browser, copy the access token' and provides examples of usage, distinguishing it from siblings like 'connect' or 'toolkit_info' via its specific authentication focus.

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 gives explicit usage guidance: it recommends adding the token as a header for a permanent connection versus pasting it for a session-only login, and tells the user to call with no args to get the link. This provides clear when-to-use and context, though it doesn't explicitly mention alternatives to this tool.

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