List All Known Devices

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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it enumerates the exact returned fields, clarifies the tool performs no network probing, and defines what 'known' means (connected, discovered, remembered, remote). No contradiction with annotations.

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 longer than average but every sentence earns its place: core behavior, field list, usage instruction, and sibling differentiation. The most important information (what the tool returns, that it doesn't scan) is front-loaded, and the field enumeration is valuable given there is no output schema.

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?

Since there is no output schema, the description carries the burden of explaining return values, which it does thoroughly by listing all eight fields. It also covers usage context, safety (read-only), and relationship to siblings. For a zero-parameter, schema-less tool, nothing an agent needs to call it correctly 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?

The tool has zero parameters, so the baseline of 4 applies. The description contains no redundant parameter information, which is appropriate since none exist. It correctly focuses on the output and usage context instead.

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 uses a specific verb ('Return') with a concrete resource ('every device Dev Studio already knows about') and clearly scopes the behavior ('without running a network scan'). It proactively distinguishes itself from get_selected_device, scan_devices, and connect_device, leaving no ambiguity about what this tool is for.

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?

Explicitly instructs the agent to use this tool as the first step to resolve a `device` argument for other tools. It also names three sibling tools and states exactly when each is the right choice, providing both positive usage guidance and clear exclusions.

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