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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false) by disclosing billing ('paid from your balance'), the return payload, the agent's opening behavior, and three distinct termination conditions: manual stop, one minute of an empty room, or credit exhaustion. That cost and lifecycle detail is exactly the context an agent cannot get from structured fields.

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-loaded with the action and the return value before moving to lifecycle rules. Prose is slightly idiosyncratic ('The Nod says it is an AI agent') but every sentence carries information.

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?

An output schema exists, so the return values needn't be spelled out, and the lifecycle/billing narrative is a real asset. However, for a billable, state-creating tool, the unexplained 'seconds' parameter and the absence of any note on re-entrancy (starting twice for the same Nod) leave meaningful gaps.

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 description coverage is 0% and neither of the two parameters is explained. The 'id' parameter's referent (presumably a Nod) is only guessable, and 'seconds' (30-7200) is never defined — it is unclear whether it caps session lifetime or is merely a hint, which directly conflicts with the stated 'leaves when... your credit ends' behavior.

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 and resource ('Starts the Nod in a fresh room on our GPU') plus what it returns (room address and a LiveKit pass). This clearly separates it from siblings like get_session, stop_session, and create_nod, which are retrieval, termination, and provisioning respectively.

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?

Usage is only implied: an agent can infer this is the tool for beginning an interactive voice session, and 'It leaves when you stop it' hints at stop_session. There is no explicit when-to-use statement, no mention of prerequisites (does the Nod need to exist first?), and no guidance on what to do if a session is already running.

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