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

Annotations declare a non-read-only, non-idempotent, non-destructive operation, and the description adds substantial context the annotations cannot: WebSocket connection, API-key authentication, hash-chained transcript sealed to the Privi chain on close, and per-message billing under a human-signed Mandate. It lacks only limits such as whether an org can hold multiple concurrent rooms or what happens on expiry.

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?

Front-loaded with the core action and scope, then layers connection, sealing, billing and auth in three compact clauses with no filler. Dense with domain terms (hash-chained, Mandate, Privi chain) but each clause carries distinct 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?

For a six-parameter, no-output-schema tool, the description covers the lifecycle (open, connect, close/seal), authentication and payment prerequisites well. The gap is return values: it references ws_url and join_code without saying that open produces them, which matters because no output schema exists to fill that in.

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 100%, so every parameter including hours, max_messages, counterparty_org_id and price_per_message_usdc is already documented with ranges and defaults. The description adds only the Mandate-payment framing for pricing, and even the payee dependency ('needs payee') is already in the schema, so this meets the baseline rather than exceeding it.

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 ('Open a live, hash-chained conversation room') plus the scope (two organizations' agents), which cleanly separates it from room_close, room_info, room_list and room_transcript. An agent can identify this as the creation primitive 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?

The description conveys the operating context (both parties connect over WebSocket with API keys, room is sealed on close) but never states when to choose this over siblings or what preconditions must hold, e.g. whether the counterparty must exist first or whether a Mandate is required before setting a price. Usage is implied rather than instructed.

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