Capture URL

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

Annotations already flag destructiveHint=true, readOnlyHint=false, idempotentHint=false, but the description goes further and names the concrete consequence: recapturing can replace an existing corpus and metadata. It also discloses the prerequisite (local media runtime) and the degraded generic fallback (no screenshots, comment fetch, or hook classification), which an agent could not infer from the annotations.

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?

Purpose first, then sibling routing, then prerequisites and side effects – a sensible front-loaded order with no filler. It is dense with compound clauses and platform jargon ('yt-dlp sites', 'hook classification'), which costs a little readability but every sentence carries information.

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?

No output schema exists, and the description covers prerequisites, destructive recapture semantics, and fallback limitations, which is most of what an agent needs. The gap is whether this is asynchronous (a get_job_status sibling exists) and what the tool returns, so the agent cannot tell if it must poll afterward.

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 the baseline is 3; the description earns above that by tying modes to parameters – 'long-video modes' maps to long_video_mode and 'generic fallback has no screenshots' tells the agent interval is inert on the metadata-only path. It stops short of explicitly naming interval or its default, which the schema already covers.

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 ('Capture a supported video URL') plus the routing mechanism and the fallback path. It explicitly contrasts itself with uoink_video, uoink_page, uoink_x, and uoink_reddit_thread, so an agent can route correctly without opening any 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 when-to-use ('non-YouTube videos or long-video modes') and when-to-use-something-else for four named siblings, each with the condition that selects it. No inference is required to choose among the capture tools.

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