TranscriptAPI — YouTube transcripts (transcriptapi.io)

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds ordering behavior (newest first) and the accepted identifier formats, but says nothing about pagination, what happens with an unresolvable handle, or rate/limit 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?

Two sentences, no filler, and the primary purpose is front-loaded before the identifier and return-value details. The return-field sentence is slightly redundant given an output schema exists, but it is brief.

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 two-parameter read tool with annotations covering the safety profile and an output schema covering return shape, the description is nearly sufficient. The only real hole is the undocumented 'limit' parameter and lack of any note on result ordering guarantees or truncation.

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 0%, so the description must carry the params. It clarifies 'channel' well by listing accepted forms (UC id, @handle, channel URL), which is real added meaning, but 'limit' is never mentioned even though it defaults to 20 and bounds the result set.

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?

States a specific verb and resource ('List the most recent uploads of a YouTube channel') plus ordering ('newest first'), so the agent knows exactly what it gets. It does not name the closest sibling, search_channel_videos, to explain why you would list rather than search, so it falls short of a 5.

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?

Usage is only implied by 'most recent uploads, newest first' — the agent can infer this is the browse-recent-content tool rather than the search tool, but there is no explicit when-to-use, when-not-to-use, or named alternative among get_playlist_videos/search_channel_videos.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context on top: playlist-order sequencing, accepted input formats, and what the response contains. It does not discuss the `limit` cap, truncation, or rate limiting, which are the natural remaining gaps.

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?

Three short sentences, front-loaded with the action and the ordering guarantee, followed by input format and downstream use. No filler or restated boilerplate.

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?

An output schema exists, so return values need not be spelled out, and the description sensibly limits itself to input format and the transcript hand-off. The only substantive gap is the unmentioned `limit` parameter and any truncation behavior it implies.

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 0%, so the description carries the burden. It documents the `playlist` parameter well ('anything with list=…' or the plain id), but `limit` is never mentioned in the description and has no schema description, leaving one of two parameters undocumented.

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?

States a specific verb and resource ('List the videos in a YouTube playlist') plus a distinguishing scoping trait ('in playlist order') that separates it from the search_* and channel siblings. An agent can pick this over get_channel_videos or search_youtube 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.

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

Explicitly positions the tool in a workflow by saying it 'Returns ids and titles for get_youtube_transcript', which tells the agent when to reach for it. It stops short of naming conditions where a different sibling should be used (e.g., unordered search or channel-wide listing).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world). The description adds genuine extra context: it works with both creator-uploaded and auto-generated captions, and translate_to consumes extra credits that scale with transcript length.

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?

Front-loads the core action, then layers input formats, return shapes, and the cost caveat. Information-dense with almost no filler, though the format enumeration is slightly long for a single sentence.

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?

With an output schema present, return values need not be detailed, yet the description still usefully sketches format shapes and flag costs. Inputs, defaults, cost implications, and caption-source caveats are all covered — an agent has everything needed to invoke it correctly.

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 0%, so the description must carry the load, and it largely does — it explains accepted `video` formats and enumerates `format` values (timestamped default, text, srt, vtt, json) with their shapes. It omits any explanation of the `language` parameter, leaving one of four params undocumented.

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?

States a specific verb ('Fetch') and resource ('transcript/captions of a YouTube video') clearly. None of the siblings (get_channel_videos, search_youtube, etc.) produce transcripts, so the tool is unambiguously distinguishable without opening a schema.

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?

Gives explicit input-format guidance (watch URL, youtu.be, Shorts, bare 11-char id) and a conditional rule for translate_to ('omit unless asked'). No alternatives are named, but the sibling set has no overlapping transcript tool, so the missing exclusions matter little.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds nothing beyond that: no mention of quota/rate limits, result ordering, or pagination behavior. The one useful addition (accepted channel identifier formats) is really parameter semantics, not 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?

Two sentences, no filler: the capability and scope come first, the input-format clarification and intent example follow. Every clause earns its place.

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?

An output schema exists, so return values need not be explained, and the annotations cover safety. However, for a search tool the description omits result-count/limit behavior and any routing hint versus its three sibling search/list tools, leaving the agent to guess on the main selection ambiguity.

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 0%, so the description carries the burden. It usefully documents that 'channel' accepts an id, @handle, or URL — the genuinely ambiguous input — but says nothing about 'query' semantics (full-text? channel-scoped?) or what 'limit' controls. Partial compensation for a total schema gap.

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?

States a specific verb and resource ('search for videos') with a tight scope qualifier ('inside one YouTube channel by keyword'), plus a natural-language restatement of the intent. This scope cleanly separates it from search_youtube (all of YouTube) and get_channel_videos (unfiltered listing), so an agent can select it 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.

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

The example phrase 'find the video where <channel> talks about <topic>' implies the intended scenario well, but the description never states when to prefer this over search_youtube or get_channel_videos, nor any exclusions or prerequisites. Usage is inferable rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety and idempotency are covered. The description adds the return fields (ids, titles, channels, durations, view counts) and a cross-tool workflow hint, but doesn't discuss rate limits, pagination, or authentication requirements. With annotations carrying the safety profile, this is adequate but not rich.

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?

Two sentences with zero waste: the first states the action and return data, the second provides a direct next-step hint. The information is front-loaded and each sentence earns its place.

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?

Given a simple two-parameter tool with annotations covering safety, an output schema (which the description doesn't need to detail), and the description providing return fields and a workflow hint, it's nearly complete. The only gap is the lack of explicit 'limit' semantics, which could confuse an agent about result count.

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 0%, so the description must compensate. It reveals that 'query' is a keyword string and that returned fields include durations and view counts, implying what 'limit' controls (number of results), but it doesn't explicitly describe the 'limit' parameter's effect or default. The description adds some meaning but leaves the 'limit' parameter undocumented.

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 states a specific verb 'Search' and resource 'YouTube for videos', and names the primary input 'by keyword'. It clearly distinguishes itself from sibling tools like get_channel_videos and get_playlist_videos, which are scoped to channels or playlists.

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 description tells when to use this tool (to search by keyword) and names a follow-up alternative (get_youtube_transcript) for reading a video's content. It doesn't explicitly rule out other scenarios or mention when to use sibling tools like search_channel_videos, but the context is clear enough.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.