system_apks_variants_download

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

With no annotations, the description bears full burden but only states the return format (base64). It fails to disclose side effects (none expected but not stated), error behavior, or dependencies like the variant's build status.

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 brief and front-loaded, but it is under-specified. It communicates the core action efficiently, but sacrifices informativeness. A balance of conciseness and completeness would be better.

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?

Given the complexity (3 required parameters, no output schema), the description is insufficient. It lacks details on return format specifics (e.g., whether it's raw bytes or encoded string) and potential error cases, failing to fully equip the agent.

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 low (33%: only packageName has a description). The description does not add meaning for versionCode or variantId, nor does it clarify their roles beyond the schema, leaving gaps for the agent.

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 states the action (download), the resource (built system APK variant), and the output format (base64). It effectively distinguishes from sibling tools like system_apks_variants_get (metadata retrieval) and system_apks_variants_list (listing variants).

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 provided on when to use this tool versus alternatives such as generated_apks_download or system_apks_variants_get. There is no mention of prerequisites like the variant being built or authentication requirements.

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