Add Externally Hosted Apk

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

With no annotations provided, the description carries the behavioral burden. It discloses a key restriction and failure mode: enterprise-only access and a 403 for normal accounts. 'Register' also implies a mutating operation. It stops short of detailing side effects or lifecycle requirements, but the most relevant access behavior is clearly surfaced.

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 two short sentences with no filler. The core purpose is stated first, followed immediately by the critical eligibility constraint, making it easy for an agent to parse quickly.

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 two-parameter tool with a detailed input schema and an output schema, the description provides the essential non-obvious context: external hosting, enterprise-only enrollment, and the 403 failure mode. Nothing critical is missing for correct invocation.

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%, and the schema already documents package_name and the externally_hosted_apk resource body, including required subfields. The description adds minimal parameter-level value beyond the schema, so the baseline score of 3 is 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?

States a clear verb ('Register'), a specific resource ('an APK hosted outside Play'), and the enterprise-distribution scope. This differentiates it from sibling upload tools like upload_apk and upload_bundle without needing to inspect their schemas.

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?

Provides concrete context for when the tool is usable: only by organisations enrolled in Play for Work private-channel distribution, and explicitly notes the 403 failure for normal developer accounts. It does not name alternative tools or say 'use upload_apk instead,' but the eligibility guidance is clear and actionable.

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