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

With no annotations, the description must carry behavioral disclosure itself. It does add useful behavioral context: the tool is invite-gated, returns a same-session contract, and should not be passed secrets as arguments. However, it does not clarify whether the operation is read-only, what happens without an invite, or what the returned contract actually contains.

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 two short sentences with no wasted words. The core purpose is front-loaded, and the security warning earns its place by addressing the most likely misuse for a zero-parameter tool.

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 zero-parameter tool, the description is mostly sufficient for invocation: the agent knows to call it, expects a capability contract, and knows not to pass secrets. However, with no output schema and no explanation of the 'capability contract' format or relationship to sibling flows, an agent may still be uncertain about what the response will look like and when exactly the tool is appropriate.

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 tool has zero parameters and schema description coverage is 100%, so there is nothing for the description to add structurally. The explicit warning 'Never pass secrets as tool arguments' reinforces the no-parameter contract and is a meaningful addition beyond the schema.

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 names a specific action ('Return') and a specific resource ('the invite-gated same-session capability contract for the encrypted agent Backroom'), which clearly identifies what the tool does. It is reasonably distinct from the sibling tools through its 'invite-gated' and 'Backroom' qualifiers, though 'capability contract' is somewhat jargon-heavy and not fully explained.

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 explicit guidance on when to use this tool instead of siblings such as s80_discover, s80_request_admission_challenge, or s80_treasury. The 'invite-gated' phrase hints at a prerequisite, but the description never states that, when admission is needed, or which alternative to choose.

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