Crawlora MCP

youtube_transcript

Read-only

Fetch a YouTube video's transcript with language, translation, JSON/text/SRT/VTT format, and timestamp options; no captions return 404 and a temporary block or rate limit returns 503. Use youtube_transcript_languages to discover available languages first.

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": {
      "id": "<id>"
    },
    "name": "youtube_transcript"
  }
}

Input Schema

Name	Required	Description
`id`	Yes	YouTube video id.
`lang`	No	Preferred transcript language.
`format`	No	Response format: json, text, srt, or vtt.
`timestamps`	No	Include timestamps in the JSON response.
`translate_to`	No	Translate the transcript to this language code.

Output Schema

Name	Required	Description	Default
`data`	Yes	The tool result payload (shape varies per tool; see each tool's docs resource).

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 5, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Annotations already declare readOnlyHint and openWorldHint, but the description adds behavior not present in structured data: 404 when no captions exist and 503 on temporary blocks or rate limits. Disclosing rate-limit and failure semantics is exactly the kind of context annotations cannot carry.

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?

One dense clause covering capabilities followed by failure semantics and the prerequisite tool. Front-loaded with the core verb+resource and free of filler; every clause carries distinct information.

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

Completeness5/5

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

With an output schema present, return-format explanation is unnecessary; the description instead covers the two things structured fields cannot: failure codes and the language-discovery prerequisite. Nothing needed to call the tool correctly is missing.

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

Parameters4/5

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 all five parameters; the description correctly reinforces the axes (language, translation, format, timestamps) without inventing syntax. It adds slight orientation value by grouping the optional parameters by purpose.

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 ('Fetch') and resource ('a YouTube video's transcript'), and enumerates the concrete capability set (language, translation, formats, timestamps). An agent can distinguish this from siblings like youtube_captions or youtube_video without opening the schema.

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

Usage Guidelines5/5

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

Explicitly routes the agent to a prerequisite sibling: 'Use youtube_transcript_languages to discover available languages first.' This names the alternative and the condition that selects it, leaving nothing to inference for the language-discovery step.

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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