Book Downloader MCP

Resolve a download URL

libgen_get_download_url

Read-onlyIdempotent

Resolve a LibGen file's direct download URL from its MD5 without downloading it, so you can pass the link to a browser or another tool.

Instructions

Resolve the direct download URL for an md5 without downloading. Useful for handing the link to another tool or a browser.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "md5": "<md5>"
    },
    "name": "libgen_get_download_url"
  }
}

Input Schema

Name	Required	Description	Default
`md5`	Yes	LibGen md5 of the file (32 hex characters), from a search result.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv4.0.1Nov 12, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds the non-obvious behavioral fact that no file transfer occurs ('without downloading'), which is real value beyond the annotations. It does not mention what happens on dead links or whether the returned URL is mirror-dependent or expiring.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, zero filler, with the core behavior and the differentiating constraint front-loaded. Nothing could be removed without losing information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter, one-value lookup with full schema coverage and rich annotations, the description covers what the tool does and why it exists. Since there is no output schema, a brief note on the return value (a URL string) would have closed the last gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% - the md5 parameter already has its format (32 hex chars), regex pattern and provenance ('from a search result') documented in the schema. The description only repeats the parameter name, adding no syntax or sourcing detail beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (resolve) and a specific resource (the direct download URL) scoped to an md5, and the phrase 'without downloading' immediately separates it from the download siblings. An agent can pick this over libgen_download without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a concrete use case - handing the link to another tool or a browser - which implies the when-to-use condition versus actually fetching the file. It stops short of an explicit exclusion (e.g. 'use libgen_download if you want the bytes'), so it is clear context rather than full routing guidance.

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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