SMI: one launch record (paid)

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

Goes well beyond the annotations: it discloses the paid nature ($0.01 in testnet USDC on Base Sepolia via x402), that the charge hits the caller's own wallet via X402_PRIVATE_KEY and that the tool makes no call without it, and that 400/404 errors are not charged. This is exactly the auth/cost context annotations cannot express, and it is consistent with readOnlyHint=true and idempotentHint=false.

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 payload fields before the payment caveats, so the critical information comes first. Minor redundancy ('Circle testnet USDC on Base Sepolia via x402, testnet USDC, no real value') costs a point but does not obscure meaning.

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 one-parameter tool with no output schema, the description covers the resource, the identifier format, the returned fields, and the full payment/auth/error-charging model. An agent has everything needed to decide and invoke 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 coverage is 100% and the single launch_id parameter is fully documented with pattern and example in the schema; the description only repeats the id concept and the same example. Baseline 3 applies since the schema carries the semantics.

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+resource+scope: 'one orbital launch by GCAT launch id', and enumerates the returned fields (date, rocket, mission, agency, payloads, mass status). The 'by id / one record' framing distinguishes it from the sibling smi_get_latest and smi_get_history without needing their schemas.

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 through the id-based lookup and gives a concrete example id, but never states when to prefer this over smi_get_latest or smi_get_history, nor any prerequisites beyond the payment note. Usage is inferable but not spelled out.

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