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

Annotations already declare readOnlyHint/destructiveHint/idempotent, but the description adds real value: it discloses that output differs by account state, includes quota reset timing, and notes the call is free. This is exactly the kind of rate-limit/auth-state context the annotations cannot convey.

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?

Sentences are short and front-loaded, with the return semantics early and the argument/behavior notes last. The closing 'Read-only, no side effects' mildly duplicates the annotations, so it is not perfectly waste-free.

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?

With no output schema and no parameters, the description carries the full burden for return values and does so for both account states, including reset behavior. Nothing an agent needs to invoke or interpret this call 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?

The tool takes zero parameters, so the baseline is 4. The description confirms this explicitly with 'Takes no arguments,' leaving no ambiguity for the agent.

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 names a specific resource (remaining supplier-search allowance) and states exactly what it returns, breaking the result into two modes (free searches left today vs. credits left with an account). An agent can distinguish this quota-lookup from data-returning siblings like discover_suppliers or get_supplier purely from the text.

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 explicit when-to-use conditions: 'Use it before a search, or after one is refused.' That is clear operational context. It stops short of naming alternatives or when-not-to-use cases, so it does not reach the top of the scale.

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