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

Annotations already disclose the safety profile (readOnly=false, idempotent=false, destructive=false). The description adds useful behavioral context: cold launches are used, the command is named, and multiple runs are averaged. It does not detail side effects like force-stopping the app, but the annotations lower the bar.

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 tightly written sentences front-load the metric and mechanism with no wasted words. Each phrase adds technical specificity.

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?

The description covers the purpose, method, and averaging behavior, and the schema fully documents serial and runs. It does not explain failure modes or device prerequisites, but for a simple measurement tool with no output schema, it is nearly 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%, but the description adds meaning beyond it by explaining that the package input is resolved to a launcher activity and that results are averaged over N runs. This clarifies how pkg and runs are used behaviorally.

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 precise metric ('Cold app-launch time (ms)'), the underlying mechanism ('am start -W -S'), and the averaging behavior. This clearly distinguishes it from siblings like android_fps and android_performance_snapshot.

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 description implies the tool is for measuring cold launch time, but it does not state when to use it over alternatives such as android_fps or android_performance_record_start. No exclusions or explicit context are provided.

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