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

With no annotations, the description carries full burden. It discloses the tool is paid ($0.04 per call via x402 on Base), returns JSON, and provides live data from specific distributors. It does not mention error handling, rate limits, or authentication beyond payment. The disclosure of cost and payment method adds transparency.

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 three sentences long, front-loading the main purpose. It efficiently lists data items and includes payment info. Slightly dense but each sentence adds value. Could be slightly tighter, but no fluff.

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?

No output schema exists, so description should inform of return content. It lists many fields (stock, pricing, lifecycle, datasheet, etc.) and mentions JSON format. For a 2-parameter tool with no annotations, this is sufficient. Missing structure details but adequate.

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 100%, so baseline is 3. The description adds value by explaining that 'country' is for regional pricing and provides an example MPN ('LM358MX/NOPB'). This goes beyond the schema descriptions, earning a 4.

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 states the tool provides comprehensive data about electronic components from multiple distributors, including stock, pricing, lifecycle status, and alternates. It uses a specific verb ('lookup') and resource ('electronic component from MPN'), and distinguishes itself from all siblings which are unrelated (e.g., brand-visibility, chem-safety, web-search).

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 description implies when to use: instead of checking multiple distributor sites individually. It mentions optional country parameter for regional pricing. However, it does not explicitly state when not to use or provide alternatives. The lack of exclusions lowers it from 5.

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