Book Downloader MCP

Download a book

libgen_download

Download a Library Genesis file by MD5, verify the downloaded file's integrity, and prevent overwriting existing files unless overwrite is enabled.

Instructions

Download one file by md5. Streams to disk with a size cap, verifies the file against its LibGen md5, and never overwrites an existing file unless overwrite=true. Returns the saved path, byte count and verification result.

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_download"
  }
}

Input Schema

Name	Required	Description
`md5`	Yes	LibGen md5 of the file (32 hex characters), from a search result.
`overwrite`	No	Overwrite an existing file instead of adding a numeric suffix.
`verifyMd5`	No	Verify the downloaded file's MD5. Defaults to true.
`downloadDir`	No	Directory to save into. Defaults to LIBGEN_DOWNLOAD_DIR or the process cwd.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv4.0.1Nov 12, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations cover the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=true), and the description adds real behavior beyond them: streaming to disk, a size cap, md5 verification, and the non-overwrite-by-default rule with a numeric-suffix fallback. It also discloses the return shape (path, byte count, verification result) despite no output schema; it omits the cap value and failure/mirror-fallback behavior.

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?

A single dense sentence, front-loaded with the action and identifier, then the side-effect and return contract. No filler or repetition.

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 4-parameter download tool with no output schema, the description covers side effects, overwrite semantics, and return values. Missing are error handling and the size-cap threshold, which are secondary but would help an agent predict failures.

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%, so all four parameters are already documented, setting the baseline at 3. The description only reinforces 'overwrite=true' and verification, adding little syntax or default detail beyond the schema.

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?

The description opens with a specific verb and resource scoped by identifier ('Download one file by md5'), which implicitly contrasts with the sibling libgen_bulk_download. An agent knows immediately this is single-file retrieval keyed on an md5 hash.

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

Usage Guidelines3/5

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

Usage is only implied: you must already have an md5, but the description never says to use libgen_search first or how this relates to libgen_get_download_url / libgen_set_mirror. No when-not conditions or prerequisites are stated.

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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