Parse an HTTP or HTTPS URL into normalized scheme, host, port, path, query, and fragment fields without fetching it.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | Absolute HTTP or HTTPS URL, up to 4,096 characters. | |
| l402_proof | No | L402 payment proof "<macaroon>:<preimage>". Omit on the first call; an unpaid call returns a 0 sat Lightning invoice and the macaroon. Pay the invoice, then repeat the call with this argument set. |
Changes observed during successful MCP inspections.
Input schema / properties / l402_proof / descriptionPrevious value: -"L402 payment proof \"<macaroon>:<preimage>\". Omit on the first call; an unpaid call returns a 5 sat Lightning invoice and the macaroon. Pay the invoice, then repeat the call with this argument set."New value: +"L402 payment proof \"<macaroon>:<preimage>\". Omit on the first call; an unpaid call returns a 0 sat Lightning invoice and the macaroon. Pay the invoice, then repeat the call with this argument set."Input schema / properties / l402_proofAdded value: +{
+ "description": "L402 payment proof \"<macaroon>:<preimage>\". Omit on the first call; an unpaid call returns a 5 sat Lightning invoice and the macaroon. Pay the invoice, then repeat the call with this argument set.",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, so safety is covered. The description usefully adds that no fetch occurs and that output is normalized, but it does not mention the L402 payment flow, error behavior, or rate limits. Some value beyond annotations, but not rich behavioral context.
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 front-loaded sentence that states the operation, input domain, outputs, and a key non-behavior ('without fetching it') with zero wasted words.
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 simple two-parameter parsing tool with full schema coverage and no output schema, the description is nearly complete: it names the input types and all output fields. It could be stronger by briefly acknowledging the L402 payment requirement, but that is already fully documented in the schema.
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%, so the schema already documents both parameters, including the L402 proof flow. The description adds no parameter-level meaning beyond what the schema provides, which is the expected baseline when schema coverage is complete.
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 uses a specific verb ('Parse') and resource ('HTTP or HTTPS URL') and enumerates the exact output fields (scheme, host, port, path, query, fragment). It is immediately distinguishable from every sibling tool, none of which parse URLs.
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 phrase 'without fetching it' implies the tool is for structural parsing rather than retrieval, but the description gives no explicit when-to-use guidance, prerequisites, or alternatives. Usage is inferable from the purpose but not stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.