list_devices

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

With no annotations, the description carries the behavioral disclosure burden. It does add meaningful context: devices are 'seen by the listener' and come 'from the database', implying a read-only, persisted view rather than a live scan. However, it doesn't disclose ordering, freshness, or any response behavior beyond what the output schema already provides.

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?

A single short sentence with no filler. It front-loads the core resource ('mobile devices') and immediately clarifies the data source and passive nature, making it easy to parse.

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 zero-parameter, read-only listing tool with an output schema, this description is nearly complete. It gives the essential selection cue ('from the database') that separates it from active scanning siblings. Explicitly naming the alternative scan_devices would make it fully complete.

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 has zero parameters and an empty input schema, so there are no parameter semantics for the description to add. The baseline of 4 applies because there is nothing missing at invocation time.

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 identifies the resource ('mobile devices') and the data source ('from the database'), and the verb 'list' is effectively carried by the tool name. However, it is a noun phrase rather than an explicit action statement, and it doesn't explicitly differentiate itself from the sibling scan_devices.

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?

Usage is implied: this tool lists devices already seen by the listener from the database, likely as opposed to actively scanning. But there is no explicit when-to-use guidance, no mention of alternatives, and no stated distinction from scan_devices, leaving some selection reasoning to the agent.

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