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

Annotations only indicate this is a mutating tool (readOnlyHint false) with no destructiveness. The description adds valuable behavioral details beyond annotations: the 24-hour duration, the 100-event capacity, and the 16 KB per-event constraint. It also hints at the separate incoming and reading channels, which is useful for understanding how the tool behaves.

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 two sentences, front-loaded with the primary purpose ('Create a 24-hour webhook inbox') and followed by a single concise constraint (limits). Every word adds value; no filler or redundant qualifiers.

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 creation tool with one optional parameter, the description covers the core purpose and constraints. However, it omits the meaning of the 'title' parameter, and since there is no output schema, it does not hint at what the return value might be (e.g., an inbox ID). The description is adequate but leaves the title parameter unexplained, which limits completeness.

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 has one optional 'title' parameter with 0% description coverage, and the tool description does not mention the title at all. The agent is left guessing what role 'title' plays—whether it is a label, a display name, or something else. Since the description fails to compensate for the schema's lack of documentation, this is a clear gap.

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 clear verb 'Create' and a specific resource '24-hour webhook inbox', and differentiates it from siblings like hookbox_delete_inbox and hookbox_read_inbox by its action. It also adds capability details (independent incoming, private reading) that make its purpose unambiguous.

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 provides clear context (24-hour lifetime, event limits) that helps decide when to use it, but does not explicitly compare it to sibling tools or state when not to use it. Since it is the only create tool among siblings, the use case is strongly implied.

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