register_session

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

With no annotations, the description carries the full burden. It discloses the core behavior (registration, enabling communication, return result) but omits potential side effects such as overwrite behavior, idempotency, or failure modes. This is moderately transparent but not deeply detailed.

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 well-organized with purpose, args, returns, and an example. Every sentence adds value without redundancy. It is front-loaded with the main purpose and then provides structured details, making it easy to parse.

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 covers the essential aspects: what it does, why it is used, the parameter specification, and an example result. An output schema exists, so return-value explanation is not strictly needed but is included. Minor gaps remain regarding edge cases, but overall it is complete.

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?

Schema coverage is 0%, but the description fully compensates by specifying task_id's purpose, allowed characters, maximum length, and giving concrete examples. This is exactly the information an agent needs beyond the bare schema type.

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 ('Register') and clearly identifies the resource ('current iTerm2 session'). It distinguishes from sibling tools like list_sessions and send_message by explaining that registration enables other sessions to find and communicate with this session.

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 states that it registers the current session, implying it is a prerequisite for inter-session communication. It does not explicitly mention when not to use it or name alternatives, but the context is clear. It also provides format constraints for task_id, which aids correct usage.

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