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

The description states the tool performs a POST to store a response ID and explains the purpose, but it does not add much beyond the annotations. Annotations already indicate the operation is non-read-only, idempotent, and non-destructive. No additional behavioral details (e.g., overwriting behavior, error handling) are provided, so the description adds only moderate context.

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?

The description is a single, concise sentence that packs action, endpoint, and rationale without redundancy. It is front-loaded with the key verb and object, and every word contributes to understanding the tool's function.

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 simple one-parameter store operation, the description conveys the essential workflow: persist the last builder response ID to continue the thread. It could be more explicit about the dependency on a prior builder streaming call, but the purpose implies it. Given the existing annotations and output schema, the description is sufficiently complete.

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?

The schema fully documents the only parameter (response_id) with a description ('Builder response id returned by the model stream'). The tool description essentially repeats this concept ('last builder response id') without adding extra format constraints or additional meaning, so it does not exceed the baseline expected given 100% schema coverage.

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 clearly identifies the action ('Save'), the object ('the last builder response id'), and the purpose ('so the next builder turn can continue the thread'). It even includes the specific endpoint, making the tool's function unambiguous and distinguishing it from sibling tools like stream-builder or start-builder-chat.

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 implies when to use the tool: after receiving a builder response from the model stream, to persist the response ID for continuity. It does not explicitly mention alternatives or when not to use it, but the context is clear enough for an agent to infer the correct usage scenario.

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