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

Annotations already state readOnlyHint=true and destructiveHint=false, so safety is covered, and the description adds real value on top: it discloses that the device is simulated and that calls are logged in device_log, which is a side effect an agent would not otherwise know. It also surfaces the possible failure reasons (verify_failed, download_failed, crash_loop), giving behavioral context about what the returned state can mean.

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 dense sentence that front-loads the resource and immediately enumerates the returned values with no filler. The long inline lists make it slightly harder to scan than separate clauses would, but nothing is wasted.

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 output schema, the description carries the burden of describing return values and does so thoroughly — state names, releases, and failure reasons. Combined with a fully documented parameter and clear read-only annotations, an agent has enough to call this correctly, though a pointer to the sibling it complements would make it 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?

Schema coverage is 100% for the single session parameter, whose description ('Session from open_app') already tells the agent where the value comes from. The description adds no further meaning about the parameter, so the baseline of 3 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?

The description names a specific resource (the phone's OTA update state) and enumerates exactly what is reported: state values, running release, held release, and last failure reason. It is clearly a read of update status, distinguishable from action-oriented siblings like apply_update and check_for_update, though it never states the verb explicitly and relies on the name for that.

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?

There is no explicit guidance on when to call this versus check_for_update, apply_update, or device_log. The only hint is that the state is 'Simulated and logged in device_log', which points at a related tool but does not describe a when-to-use condition or any prerequisite beyond the session.

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