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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses that the tool creates a first-class reply, implies acknowledgment, and that passing lease_id fences stale workers. These are important side effects. However, it does not mention other behaviors like error handling or whether the reply is sent directly to the sender, but the disclosed information is valuable.

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 and key usage detail (lease_id). Every word contributes value; there is no redundancy or filler.

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?

While the description covers purpose, usage, and key side effects, it lacks details on the reply's recipient, any effects on the inbox, and error conditions. For a mutation tool with no output schema and no annotations, this is a moderate gap. The description is adequate but leaves some operational questions unanswered.

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 description coverage is 50%. The description adds meaning for lease_id by explaining its role in fencing stale workers, which goes beyond the schema. It does not add information about message_id or message, though message_id is required and self-explanatory. Given the partial schema coverage, the description partially compensates but not fully.

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 states the tool's function: replying to a message from bus_inbox, creating a first-class reply, and implying acknowledgment. It also mentions the lease_id for fencing stale workers. This differentiates it from siblings like bus_ack and bus_send, making 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 usage context: use this tool to reply to a message received via bus_inbox, and pass the lease_id to fence stale workers. It does not explicitly mention when not to use it or point to alternatives, but the context is sufficient for an agent to infer the appropriate situation.

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