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

Despite lacking annotations, the description discloses a critical side effect: 'Can only be called once per session_key, thereafter the session_key is invalid.' This goes beyond the basic schema and informs the agent of non-idempotency and invalidation. No other behavioral traits are mentioned, but for a simple exchange, this is valuable.

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 three lines: a purpose statement, a usage constraint, and structured param/return annotations. It is front-loaded with the core behavior and every line adds information. No 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 one parameter, an output schema, and no annotations, the description covers the primary function, the one-time-use behavior, and the return type at a high level. It omits error behavior and what the token should be used for, but these are partly covered by the output schema. Overall, it's reasonably complete for such a simple 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?

Schema description coverage is 0%, so the description needed to clarify the session_key. It says 'The customer provided session_key,' which adds minimal context (that it originates from the customer) but doesn't explain format, constraints, or example. The param doc is nearly redundant with the parameter name.

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 specifies a concrete action: 'Returns a token given a customer provided session_key.' This clearly identifies the resource (token) and input (session_key). It doesn't explicitly contrast with the sibling netfluid__session_2_token, but the one-time-use caveat adds a distinguishing detail.

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?

There is no guidance about when to use this tool versus alternatives like session_2_token. The one-time-use warning is more of a constraint than a usage directive. No context about prerequisites or typical workflow is given.

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