Hot-reload the upstream registry

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

Goes well beyond the annotations by describing concrete effects: new servers appear, removed ones are disconnected, unchanged ones keep their connections, and a broken config fails safely leaving the current setup running. That covers side effects, existing-state preservation, and failure semantics. What's missing is whether the operation blocks or interrupts live traffic, and whether a partial config can be applied.

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?

Two tight sentences, zero filler. The hot-reload guarantee is front-loaded in capitals, and the second sentence handles failure behavior without restating anything.

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?

With no parameters and no output schema, the description covers the two things an agent actually needs: what changes take effect and what happens on a bad config. It does leave out what a successful call returns (counts of added/removed servers) or how failure is surfaced, which matters slightly more given there is no output schema.

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 tool takes no parameters, so the schema has nothing to document and the description need not compensate — baseline 4 applies.

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?

States a specific verb and object ('Re-read servers.json and apply changes') plus the key differentiator from a full restart ('WITHOUT restarting the gateway'). The operation is unambiguous and distinguishable from the read-only siblings such as gateway_status and list_servers.

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 implied trigger is clear: this is what you call after servers.json has changed, and the alternative (restarting the gateway) is implicitly ruled out by the 'WITHOUT restarting' phrasing. It stops short of an explicit 'use this when / do not use when' statement or a note about concurrent in-flight calls.

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