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

With no annotations, the description carries the load and does something genuinely useful: it discloses that this is derived from web decompile recon rather than the official API, and that it rides the Play Console web session instead of the service account. That tells the agent the call is unofficial and session-dependent, which is the key risk. It does not cover failure modes, rate limits, or what an unavailable/error result looks like, so not a 5.

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 short sentences, zero filler, with the purpose front-loaded and the caveat about provenance following immediately. Nothing here could be cut without losing signal.

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?

There is no output schema, so the description should say what a call returns (a boolean, an availability reason, a name-conflict detail) and what happens when the web session is stale. The auth prerequisite is covered in the schema rather than the description, which helps, but the return shape is left entirely unspecified for a check tool whose whole value is its answer.

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 developer_id, package_name, google_account_email, and notification_message are already fully documented, including the instruction to call list_accounts first and confirm with the user. The description adds no additional parameter meaning beyond the schema. Baseline 3 applies.

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 specific verb and resource ('Check whether a package name is available') and scopes it to the pre-creation step, which implicitly distinguishes it from create_app and the other app-mutating siblings. A dedicated sibling differentiation sentence is absent, but the intent is unmistakable.

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 phrase 'before creating a new app' is an explicit usage trigger that tells the agent when to reach for this tool rather than calling create_app directly. There is no statement of when NOT to use it or what to do if the check is inconclusive, so it stops short of a 5.

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