smart_fetch

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly discloses the critical side effect: automatic negotiation and payment of invoices via Modexia AgentPay when a 402 with WWW-Authenticate is received. This is a significant behavioral trait (potential monetary cost) that would otherwise be unknown. However, it omits other behaviors like timeout, response format, or what happens on non-402 errors, which prevents a 5.

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 two sentences, front-loaded with the primary action ('Fetch an external resource via HTTP') followed by the conditional payment behavior. Every sentence adds essential information without redundancy or filler. It is concise yet complete in its own scope.

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?

The description covers the core behavior (fetch + auto-pay) but lacks an output schema and does not describe what the tool returns, error handling, or prerequisites. Given the tool can trigger payments, additional context would be expected for safe usage. Still, the unique payment flow is adequately described, earning a mid-level score.

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 input schema has minimal descriptions (0% coverage), and the description does not compensate by explaining the 'url' or 'method' parameters. It does not specify that 'method' likely requires an HTTP verb (GET, POST, etc.) or provide any allowed values. The overall fetch concept is clear, but parameter-level semantics are left entirely to the agent's inference, which is insufficient given the low schema coverage.

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's function: 'Fetch an external resource via HTTP'. It also distinguishes itself from all financial sibling tools (get_balance, transfer, etc.) by describing its unique payment negotiation behavior on 402 responses. The verb 'fetch' plus resource 'external resource via HTTP' is specific and unambiguous.

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 usage whenever an external HTTP fetch is needed, especially when the resource may require payment. It does not explicitly mention alternatives or when not to use the tool, but the context of sibling tools (all financial/channel operations) makes this the obvious HTTP fetch tool. The lack of exclusions is a minor gap.

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