Wait for the agent's reply

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

With no annotations, the description fully discloses key behavioral traits: blocking until turn finishes or approval/input is requested, returning the latest assistant message or pending request, and timeout behavior (default 120s, max 300s) returning current state. This goes beyond what the schema provides and gives the agent a clear mental model of the tool's side-effect-free, wait-for-request nature.

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 with no fluff. The first sentence states the core blocking and return behavior, the second gives usage context, and the third covers timeout. Every sentence earns its place, and the format is front-loaded with the primary action.

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?

Without an output schema, the description must describe return values, which it does ('latest assistant message or the pending request'). It also covers when to use the tool and timeout behavior. For a simple 2-parameter wait tool with no annotations, this is complete and leaves no critical 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%, so the description must compensate. It adds meaning for both parameters: threadId is implied via 'the thread's current turn' and timeoutSeconds is explained with default and max values. It does not mention the minimum of 5s (schema provides that) or explicitly state optionality, but the default implies it. Overall, the description enriches parameter understanding.

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 ('Block') and clearly identifies the resource (thread's current turn). It distinguishes itself from siblings by specifying it returns after the turn finishes or when approval/input is requested, and it is explicitly positioned after send_message/create_thread. This is a specific and unambiguous purpose.

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 explicitly states 'Use after send_message or create_thread for a single round-trip', providing clear usage context and differentiating it from other waiting tools. It does not explicitly name alternatives or exclusions, but the context is clear enough for correct selection.

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