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

With no annotations, the description carries the full behavioral burden. It discloses the one-query-per-call scope limit and where results land (conversation vs. disk), which is genuine added context, but it says nothing about failure modes (missing subtitles, unavailable language), rate limits, or auth requirements.

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, front-loaded with the core action, followed by the scope constraint and the alternative. The embedded CLI snippet is slightly heavy for the payload but is load-bearing and earns its space.

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 no explanation, and all four parameters are documented in the schema. The only real gap is behavioral detail around language/subtitle_origin fallback, which is minor given the structured data available.

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%, so tag, language, video_id, and subtitle_origin are all already documented. The description adds no syntax or behavior detail for language fallback or subtitle_origin selection, so the baseline of 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?

Specific verb ("Retrieve") plus resource ("subtitles") plus scope ("one YouTube video") makes the purpose instantly clear. It does not explicitly distinguish itself from nearby siblings like get_youtube_video_metadata or get_youtube_search_results, so it stops 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?

It states the operating constraint (one query per call) and names an escape hatch — the ScrapingBee CLI — with the two conditions that select it (many queries, or writing to disk). The alternative offered is a CLI rather than a sibling MCP tool, so it gives clear context without exhausting the when/when-not space.

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