SMI: one print (paid)

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

Annotations cover safety (readOnly, non-destructive, openWorld), but the description adds behavior they cannot convey: per-call cost, payment rail (x402, Circle testnet USDC on Base Sepolia), that value is testnet-only, which credential is debited, that no network call occurs without the key, and that failed requests are not billed.

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?

Front-loads identity and scope, then payment mechanics, then error billing. Dense but every clause is load-bearing (cost, credential, no-call condition, non-billing errors). Slightly packed into one paragraph rather than split, but no filler.

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 paid, single-param lookup with no output schema, it covers cost, prerequisites, failure billing, and content scope ('information only; contains no market prices'). It stops short of describing the shape of the returned print, which is the only meaningful gap.

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 already carries both the pattern and the '2026-W39.r7' example, so the description's example repeats rather than extends the schema. Baseline 3 for a fully documented single-parameter schema.

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?

States a specific verb and resource: fetch one archived weekly SMI print by print id, with a concrete id format example (2026-W39.r7). This distinguishes it from siblings smi_get_latest (latest) and smi_get_history (range), and the publisher is named.

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 invocation context: it is a paid call ($0.01 USDC), requires X402_PRIVATE_KEY in the caller's environment, and 'without it the tool makes no call.' It also notes errors 400/404 are not charged. It does not explicitly route the agent between this and smi_get_latest/smi_get_history, so it stops short of full alternative guidance.

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