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

Beyond the annotations, the description discloses cost ('up to max_coins'), temporary limits ('1 hour, 20 events'), retry/idempotency behavior, and read/write key separation. There is no contradiction with readOnlyHint=false or destructiveHint=false.

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 dense sentences front-load the core action and limits, then add the most important operational caveats. There is no filler or redundancy.

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?

The description covers cost, duration, event quota, retry behavior, and access modes. Since an output schema exists, return-value details are not the description's responsibility, and no needed calling context is missing.

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 clarifies max_coins and request_key semantics, but api_key is left to its title alone, leaving one required parameter under-explained.

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 identifies a concrete resource ('temporary callback inbox') and a clear action: spend coins to obtain it. It is readily distinguished from sibling tools like delete_callback_inbox and read_callback_events.

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 provides actionable usage guidance: reuse request_key on retries and note that the receive URL is write-only while reads need the utility key. It does not explicitly route to sibling alternatives, but the intended usage context is clear.

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