Wait for the next DualStream event

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

Beyond the readOnlyHint annotation, the description discloses that the whole session is held, there is no server-side timeout, and the call fails retryably if the DualStream connection drops. These are critical behavioral traits that an agent must know to avoid blocking the user unexpectedly.

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?

Although longer than typical, every sentence earns its place: the block behavior, the session warning, explicit usage rules, the reaction loop, and failure mode. It is front-loaded with the core behavior and structured for quick comprehension.

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 blocking, session-holding tool with no output schema, the description covers all necessary operational context: return semantics, connection loss handling, retryability, and interaction pattern. An agent has enough to invoke it safely and 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?

Schema already covers both parameters at 100%, so baseline is 3. The description adds meaningful nuance by explaining since_seq as a cursor from the previous call ('pass the last_seq from your previous call') and providing a concrete events filter example. This enriches, but does not radically change, schema semantics.

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 opens with a clear verb+resource+behavior: 'Block until a control event arrives (or return immediately if matching events are already buffered past since_seq).' This distinguishes it from non-blocking sibling tools like get_recent_events and leaves no ambiguity about what the tool does.

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 explicit when-to-use ('Only call it when the user has EXPLICITLY asked you to listen for events') and when-not-to-use ('Never use it to wait for consent approval or as a convenience between steps... tell the user what to do, end your turn, and retry'). It also outlines the live-reaction loop pattern, cementing usage context.

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