joinRoom

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

Beyond annotations (idempotent, non-destructive), description adds critical behavioral details: the return of an 'agentToken' for stateful subsequent calls and that 'new messages are delivered as notifications', explaining the delivery mechanism not covered by annotations.

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 with zero waste: purpose declaration, return value/workflow implication, and notification behavior. Each sentence delivers distinct value regarding functionality, output, and side effects.

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?

Despite lacking an output schema, description compensates by documenting the critical return value (agentToken) and notification behavior. Combined with complete input schema and annotations, the description provides sufficient context for invocation.

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?

With 100% schema description coverage, the structured fields adequately document parameters (roomId syntax, agentName purpose, password optionality). Description provides no additional parameter semantics, meeting the baseline expectation for high-coverage schemas.

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?

Description uses specific verb 'Join' with resource 'room' and explicitly qualifies it as 'existing room', clearly distinguishing it from sibling createRoom. The scope is precisely defined.

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?

Provides clear context that this is for 'existing' rooms (implied alternative: createRoom) and states it 'Returns an agentToken for subsequent calls', indicating prerequisite status for tools like sendMessage. Lacks explicit 'when not to use' exclusions.

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