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

With no annotations provided, the description carries the full burden. It discloses the pre-flight GET /v1/agents/{id} check, the requirement that offer.counterparty be set, and the signing requirements (same as start_session). It does not mention side effects or reversibility, but for a session-offer tool that is likely acceptable; it is transparent about the essential behavior.

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?

Three sentences that are dense and front-loaded. The purpose is stated first, usage guidance and behavioral notes follow efficiently. No wasted words.

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?

The tool is complex (nested objects, signing, pre-flight) and has no output schema. The description does not mention the response format or error cases beyond 'clear error'. It covers the key decision factors and pre-flight, but an agent might need more on what to expect after a successful call. Given the complexity, a bit more detail on return values would be helpful.

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 must compensate. It adds meaning for offer.counterparty (must be set) and the signing process, but does not explain the auth object, offerSignature, or other offer fields. The schema itself has detailed descriptions for auth properties, so the agent can get details there, but the description only partially covers the parameter space.

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?

States a specific verb (invite) and resource (known counterparty to a session), and explicitly differentiates itself as a convenience wrapper around start_session. The first sentence makes it clear what it does and how it differs from the sibling.

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?

Explicitly states when to use (you already know the other agent's id) and when not (use start_session for open invites). Also explains the pre-flight check that improves error clarity, giving the agent a clear decision path.

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