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

Annotations already establish read-only, idempotent, non-destructive behavior, so the description only needs to add content-level context. It usefully states that the output includes steps, checks, and links, but it does not describe response format, localization behavior, or any additional constraints besides what the schema covers.

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 entire definition is one front-loaded sentence that moves from core content to secondary support links. No words are wasted and all key topics are listed without redundancy.

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 simple, optional-parameter guide tool whose safety profile is covered by annotations and whose parameters are simple enums, the description is complete enough to call correctly. It tells the agent what will be returned (steps, checks, links) and no output schema is needed to understand the result.

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 50%: the lang parameter is described but device is not. The description partially compensates by listing 'iPhone or Android,' which maps to device's enum, but it does not explain lang's effect on the returned guide beyond what the schema already says. Overall, this is adequate but not enriched.

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 identifies a concrete resource—setup steps, pre-purchase checks, and links—and the title reinforces that this is the install/start guide. It is clearly distinct from sibling tools about plans, pricing, and coverage, though it lacks an explicit verb like 'retrieves' or 'returns.'

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?

Usage is implied: an agent would choose this tool for setup or pre-purchase questions, while alternatives like estimate_data or search_plans are about planning/selection. It does not explicitly state when to use it over siblings or list exclusions, but the content description gives enough context for a reasonable choice.

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