Join using a short code

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

With no annotations, the description carries the full burden and does so well: it discloses that codes expire after a minute, work only once, and that a silent arrival is indistinguishable from absence unless the user speaks.

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?

Two sentences carry the entire operational picture: purpose in the first sentence, constraints and behavioral caveat in the second. No filler or redundant restating of the schema.

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 single-parameter tool, the description is nearly complete: it covers the source of the parameter, its constraints, and the expected interaction pattern. It does not explicitly describe return values or error behavior on expired/invalid codes, but the expiry warning makes the main failure mode inferable.

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 fully documents the code with a pattern, but the description adds meaning by identifying the code as coming from share_code and emphasizing that it is short-lived and single-use, which is valuable for correctly obtaining the parameter.

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 first sentence states a specific verb ('Join'), the exact resource (a room), and the distinguishing mechanism ('six-digit code ... instead of the full six-word id'), which clearly separates it from join_room.

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?

It explicitly contrasts with join_room by saying the code is used instead of the full id, names the source tool share_code, and gives post-join guidance ('say something, then wait'). The one-minute expiry and single-use warning also clarify when the tool is viable.

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