google_pro_benefits

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

With no annotations supplied, the description carries the full burden and does most of it: it declares 'Read-only, free and offline' and discloses a real environmental dependency, that Flow/Gemini app/Notebooks/AI Mode entries appear only under GEMINI_PRO_ENABLE_BROWSER=1. It does not say whether the benefit list is static or version-dependent, which is the one behavioral detail left implicit.

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 core purpose and the 'call it first' rule are front-loaded in the first two lines, with the environment caveat and return shape following in priority order. The 'Returns:' block mildly repeats the earlier 'which tool reaches each part' phrasing, but the restatement is short and does clarify the per-benefit entry shape.

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 zero-parameter discovery tool with an output schema already defined, the description supplies everything else an agent needs: what it enumerates, when to invoke it, its safety/cost profile, and the environment flag that changes its contents. Nothing material is missing.

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?

There are zero parameters, so there is nothing for the description to disambiguate and the baseline is 4. It correctly signals a no-argument call by describing the tool purely in terms of what it enumerates.

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 opens with a specific verb and resource ('List everything a Google AI Pro plan includes') and immediately clarifies the added value: mapping each benefit to the server tool that reaches it, or the reason it is unreachable. That framing distinguishes it from every sibling, which are action tools (gemini_ask, video_generate, jules_start) rather than a capability-discovery index.

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?

It gives an explicit routing rule: 'Call it first when the user asks what their plan can do or which tool to use.' That is a concrete trigger condition plus an ordering instruction, which is exactly the when-to-use guidance an agent needs for a discovery tool.

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