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

Annotations already declare the mutation/idempotency/open-world profile, and the description stays consistent with them while adding context annotations cannot express: the expert receives an out-of-band link and joins from a phone, the room returns 'room state and the host rules', and crucially 'No money moves; the job's price covers the expert's time.' It omits room lifetime and what happens to the thread on close.

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?

Five tight sentences, front-loaded with the core action and status prerequisite, then workflow, then return values, then the cost model. No sentence is filler; the payment disclaimer earns its place by preempting a likely agent question.

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?

With no output schema, the description carries the return-value burden itself ('Returns the room state and the host rules') and covers the prerequisite, the relay loop via room_wait, and the billing behavior. Nothing an agent needs to call this correctly is missing.

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 only 33% (context is documented, job_id and customer_token are bare strings). The description partially compensates by implying job_id must reference an ACCEPTED job, but it says nothing about customer_token's role or the maxLength/format of context. Adequate but incomplete against a real coverage gap.

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?

Opens with a concrete verb+resource+scope: 'Opens a three-way room on a job the expert has ACCEPTED (status accepted).' It names the participants (your user, you, the expert) and the relay mechanism, so an agent can distinguish it from ask_human, call_human, or summon_expert without opening any schema.

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?

Gives an explicit selection condition: 'Use it when the question needs the expert to ask back before answering — most high-stakes questions do,' plus the prerequisite that the job must already be in 'accepted' status. It points forward to room_wait as the follow-up tool but never names the sibling it replaces (e.g. summon_expert or ask_card), so the agent must infer the boundary.

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