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

With no annotations available, the description carries the full burden, and it does well: it discloses rate-limit and capacity validation, mutual eligibility checks, the non-member invitation expiration window, and the distinction that invitations do not count against the open-rendezvous limit. It does not detail return values or error behavior, but the core behavioral traits are transparent.

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 compact and front-loaded: the first sentence states the core action, and the second sentence flows naturally from member behavior to invitation behavior and validations. Every clause adds useful information without repetition or filler.

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 four-parameter schema and no annotations, the description covers the important operational constraints: candidate source, conditional message requirement, expiration, and validation checks. It does not address the optional claims parameter or describe the response/confirmation shape, but for a state-opening mutation it is sufficiently complete for an agent to invoke 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 schema already documents candidate_id, message, and participant_secret, and the description adds important conditional meaning beyond the schema: message is required when the candidate is a registered non-member, and candidate_id comes from discover. The claims parameter remains undocumented in both description and schema, which keeps this from being a 5.

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 uses a specific verb-resource pair, "Open a private rendezvous with a candidate from discover," and immediately distinguishes the two behavioral modes (member vs. registered non-member). It clearly separates this from related sibling tools like rendezvous_read and rendezvous_send by focusing on the opening action.

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 clear context for when to use it: with candidates from discover, and it distinguishes behavior for members versus registered non-members. It does not explicitly name alternatives or state when not to use this tool, but the mode-based guidance effectively directs the agent's choice of parameters and expectations.

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