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

Beyond the readOnlyHint annotation, the description adds critical behavioral details: it is free and doesn't consume tokens, and it specifies the mandatory output contract for handling 'Account notice:' paragraphs. These are non-obvious behaviors that materially affect how an agent should process the result, so the description fully carries the burden.

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 well-structured: purpose first, then usage, then output contract. The output contract section is verbose but essential and unambiguous. No filler words; every sentence serves a functional role, so it earns high marks for conciseness despite moderate length.

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, read-only, parameter-free tool, the description covers everything an agent needs: what it does, when to call it, how to interpret its output, and special formatting requirements. The lack of an output schema is compensated by the explicit output contract instructions, making the tool fully self-contained.

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?

With zero parameters, the schema provides no semantic content. The description doesn't need to explain parameters, but it does describe what the tool returns (balance figures) and how to report them, adding value beyond the empty schema. Baseline for 0 params is 4, and the description meets this without overreach.

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 identifies the tool as reporting the caller's AMZScout token balance (remaining, used, and limit), a specific resource and action. This is distinct from the sibling tools, which all perform analysis or search functions, leaving no ambiguity about the tool's purpose.

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 explicitly states when to use the tool: in response to token balance queries or when a call fails on quota. It also provides a concrete 'How to use' section with example user prompts, and clarifies the free nature (no token charge), which is a key usage consideration. No alternatives are needed since it's the only usage tool.

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