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

Annotations already indicate this is a mutating but non-destructive operation. The description adds the enrollment effect and post-join capabilities, plus the source of the code via agent_mesh_invite. It doesn't cover permission requirements or reversibility, but the core behavior is 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?

Three sentences with no waste: action + source, postcondition, and alternative. The essential task is stated first, and the sibling routing is at the end.

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 an output schema and complete parameter schemas, the description supplies the remaining context—what the machine gains from joining and how to create instead. An agent has everything needed to call 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?

With 100% schema description coverage, the schema already documents both parameters. The description reinforces the code's provenance ('from agent_mesh_invite') and clarifies label as 'THIS machine', a small but useful addition. Baseline 3 is appropriate since schema does the heavy lifting.

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 ('enrolls') and resource ('existing agent mesh'), and explicitly names the sibling it is not ('To create a mesh instead of joining one, use agent_mesh_create'). An agent can tell it apart from agent_mesh_create without opening schemas.

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: use when the user has a pairing code from agent_mesh_invite on another machine. Explicitly routes to agent_mesh_create for the create case, covering the main alternative. The reference to agent_mesh_invite also clarifies the prerequisite flow.

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