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

Beyond the destructive/open-world annotations, the description adds useful behavior: passing null or empty clears the prompt, the change only affects the next processed recording, and existing recordings are not re-analysed automatically. It also names the required write scope.

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, front-loaded with the core action and packed with timing, clearing, and scope details. There is no wasted language.

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 mutation tool with rich annotations and fully described parameters, the description covers the important gaps: how to clear, when the change applies, and the required permission. No output schema is needed for this setting update.

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 account, workspace, and customPrompt are already well documented. The description adds that an empty string also clears the prompt, but otherwise relies on the schema for parameter meaning.

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 states a specific verb and resource: update the workspace's custom prompt. The word 'workspace's' distinguishes this from the sibling call-, event-, and series-level custom prompt setters.

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?

It explains when the change takes effect and points to hub_regenerate_summary for existing recordings, giving a clear alternative for that case. It does not explicitly compare against the call/event/series custom prompt tools, but the workspace scope is clearly stated.

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