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

The description discloses behavioral details beyond annotations, such as the token being non-expiring if set via config versus session-only if pasted, and that calling with no arguments returns a link. It clarifies the idempotentHint by explaining that authentication can be set or updated. No contradiction with annotations; it complements them well.

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 at three sentences, but the second sentence is long and might be clearer with bullet points. However, every phrase carries essential information—the authentication flow is fully explained without fluff.

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 a single optional parameter, the description covers both call patterns (with and without token) and the recommended permanent configuration. It omits error handling or edge cases, but these are out of scope given the low complexity and lack of output schema.

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?

With 0% schema coverage, the description fully compensates by explaining the 'token' parameter as a JWT, how to pass it ({ token: "<jwt>" }), and that omitting it triggers a link response. This adds significant meaning beyond the minimal schema definition.

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 by logging in and providing an access token. It distinguishes itself from siblings by focusing on authentication flow, with specific actions like 'log in in the browser' and 'call with { token: ... }'. The resource (authentication) and verb (get token, store) are explicit.

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 when-to-use guidance by explaining two usage modes: no-arg for a link and token-based for session login, plus a recommendation to use a config header for permanent access. It implies when to use it (when needing authentication) but does not explicitly name alternative tools like 'connect' for comparison, though the context is clear.

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