SMX: market detail from the agent API (paid)

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

Annotations already declare readOnly/openWorld/non-idempotent, but the description adds substantial context they don't carry: the $0.01 charge in testnet USDC on Base Sepolia via x402, the X402_PRIVATE_KEY requirement (no key = no call), and that 400/404 responses are not billed. This is exactly the extra behavioral detail an agent needs before invoking a paid tool.

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?

A single dense paragraph that is front-loaded with the endpoint and resource, then payment mechanics. Every clause earns its place, though the payment sentence is somewhat packed.

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, the description compensates by listing the returned fields, and it fully covers payment, auth, and error-charging behavior. An agent has everything needed to call it correctly.

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 description coverage is 100% and the single parameter is fully documented in the schema (pattern plus 'Market id from smx_list_markets'). The description adds no further parameter meaning, so the baseline of 3 applies.

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?

Names a specific verb+resource ('market detail'), the exact endpoint (GET /agent/markets/{id}), and enumerates the returned fields (status, outcome, midpoint, minimum order, book summary). It clearly distinguishes itself from the sibling smx_get_market by being the paid variant.

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?

Gives clear conditions around cost and the wallet-key prerequisite, and states that errors are not charged. However, it never explicitly tells the agent to prefer smx_get_market when payment is unnecessary, leaving the paid-vs-free choice to inference from the name.

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