mesh_join_room

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

With no annotations, the description does the heavy lifting: it discloses that joining starts background watching, publishes participant_joined, and is idempotent. It leaves out failure modes and return behavior, but the key side effects are clearly surfaced.

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 front-load the core purpose, state behavioral effects, and close with a compact workflow. Every clause earns its place; there is no filler or redundant restating of the tool name.

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 simple two-parameter tool, the description covers the discovery path, side effects, idempotency, and subsequent tool routing. The optional host is documented in the schema. It lacks explicit return-value or failure information, but the overall calling context is clear.

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 room_topic and host at 100% coverage, so the description doesn't need to compensate. It adds no extra parameter format, constraints, or examples beyond what the schema provides, so the baseline of 3 applies.

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 action—joining a room—and identifies the resource by topic. It also nods to mesh_rooms for discovery and to downstream tools for talking/reading/leaving, making the tool's role distinct from its siblings.

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?

Tells the agent when to use this tool: after learning a topic via mesh_rooms or out of band. It also routes follow-up actions to mesh_say, mesh_read_inbox, and mesh_leave_room. It does not explicitly exclude alternatives like mesh_open_room, so it stops short of a 5.

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