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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the shape of the payload — per-language titles, summaries, chapter lists with page anchors and YouTube timestamps, plus Markdown and JSONL link variants — which matters because there is no output schema.

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: purpose first, then the returned payload. Dense but tightly packed with useful nouns; slightly heavy on parenthetical detail, yet every clause describes real return content an agent would want to know.

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 no output schema, the description carries the return-value burden and does so adequately by enumerating the content types and link formats. It does not cover failure behavior for unknown ids or payload size, which are minor gaps for a single-item read.

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% and the schema's own id description supplies the example and provenance (YouTube video id from search results). The description adds nothing about the id parameter beyond what the schema already says, so baseline 3 applies.

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: retrieve a single episode by id, and lists the concrete contents returned (titles, summaries, chapter list, full-text links). It is distinguishable from search_episodes and the list_* siblings by being a single-item fetch, though it never names them explicitly.

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 implied: use this when you already have an episode id (the schema even says 'a YouTube video id from search results'), which hints at a search-then-fetch flow. There is no explicit statement of when to prefer search_episodes or the list tools, and no mention of what happens with an invalid id.

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