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

No annotations are provided, so the description carries the behavioral burden. It discloses the underlying mechanism (`dumpsys gfxinfo`) and the exact metrics collected, which implies a read-only query and helps an agent understand what will happen. It does not mention prerequisites like app foreground state or whether any state is reset, but for a stat-retrieval tool the disclosed details are reasonably transparent.

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, front-loaded sentence that packs in the tool's purpose, implementation method, and metric list without any filler. Every phrase adds value.

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 simple read-only tool with two straightforward parameters and no output schema, the description gives a complete enough picture: an agent knows the target package, the serial source is in the schema, and the expected output metrics are enumerated. It doesn't specify the exact return structure, but that is a minor omission for a stats tool.

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 description coverage is 100%, so the parameters `serial` and `pkg` are already fully documented in the input schema. The description adds meaning only for `pkg` by showing the metric scope, which is useful but not necessary. The baseline of 3 applies because the schema does the heavy lifting.

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 (a package) and the specific metrics (FPS/jank stats, total frames, jank %, percentiles, missed vsyncs), making the tool's function obvious. It doesn't use an explicit verb like 'retrieve' but is specific enough to distinguish from siblings like android_app_launch_time and ios_fps.

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?

No guidance is given on when to use this tool versus alternatives such as android_performance_snapshot, android_app_launch_time, or ios_fps. The description implies a performance measurement use case but provides no exclusions or sibling comparisons.

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