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

Annotations declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful behavioral context beyond that: the analysis examines shared signing certificates, SDK/analytics identifiers, and other ownership signals, and requires *completed* jobs. It does not describe cost, latency, or failure modes for incomplete jobs.

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 states the action, the operands, and the output signals with no filler. Every clause earns its place.

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?

An output schema exists, so return values need not be explained, and annotations carry the safety profile. The description covers purpose and the key input constraint, but omits what happens if a job is not completed or how the two job IDs are obtained, leaving a small gap.

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%, and the schema itself already states that job_id_a must be a different app than job_id_b, so the description only repeats that constraint. No extra syntax, format, or ID-lookup guidance is added, making the baseline 3 appropriate.

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 (Compare) on a concrete resource (two completed apk-teardown jobs) and names the analysis goal (signals of common ownership). The 'DIFFERENT app, not another version' constraint implicitly distinguishes it from the apk_teardown_diff sibling, though no sibling is named explicitly.

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 constraint that both jobs must be different apps (not two versions of one) implies the intended usage and steers away from the diff tool. However, it never explicitly states when to prefer this tool over apk_teardown_diff or what preconditions (both jobs completed, same pipeline) are required.

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