GET https://ticks.bnm.farm/mariners-d9 — $0.05 USDC on Base to 0xf59621FC406D266e18f314Ae18eF0a33b8401004. USCG D9 / Great Lakes LNM Unpaid returns HTTP 402. After a valid X-PAYMENT, the same URL returns JSON. Not a new SKU.
| Name | Required | Description | Default |
|---|---|---|---|
| x_payment | No | Optional x402 X-PAYMENT value forwarded to the paid GET as the X-PAYMENT header. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the transparency burden and does well by disclosing the $0.05 USDC payment requirement, the 402 response when unpaid, and JSON after a valid X-PAYMENT. It is slightly marred by the cryptic 'Not a new SKU' sentence but otherwise reveals key runtime behavior.
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 short but grammatically choppy and includes cryptic fragments such as 'USCG D9 / Great Lakes LNM Unpaid returns HTTP 402' and 'Not a new SKU.' It front-loads the URL and payment detail, but clarity suffers from unconventional punctuation and unclear phrasing.
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 explains how to obtain JSON (pay and pass X-PAYMENT) and what happens if unpaid, but it gives no details about the response structure, data fields, or other possible error codes. It is workable for a simple paid GET but not fully contextual.
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 only parameter, x_payment, is described in the schema as an optional x402 X-PAYMENT value forwarded as a header, and the tool description reinforces how it unlocks the response. This fully explains the parameter's meaning and usage, though the tool description adds little beyond the 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?
The description specifies a GET endpoint for USCG D9 / Great Lakes Local Notice to Mariners data and includes a payment condition. It identifies the resource via 'USCG D9 / Great Lakes LNM' but does not explicitly state that the tool returns LNM content or contrast it with sibling district tools.
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?
No explicit guidance is given for when to use this tool over sibling mariners-d1/d5/d7/d8/d11/d14/d17 tools. The resource label 'USCG D9 / Great Lakes LNM' implies a geographic district, but the description does not state selection criteria, exclusions, or alternative tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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