Capture web page

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

Beyond the annotations (destructiveHint=true, openWorldHint=true), the description discloses what actually gets replaced ('Recapturing a source can replace its saved corpus and metadata'), a failure mode ('video_id is null if extraction succeeded but persistence failed'), renderer behavior ('Crawl4AI renders locally when available; static fallback has no screenshot'), and that the result is saved locally. This adds real operational context for a mutation tool.

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?

The description is front-loaded with the core action, then routes to alternatives, then covers authorization, rendering, return behavior, and recapture side effects. Every sentence contributes a distinct decision-relevant fact, and there is no redundant filler.

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 mutation tool with no output schema, the description covers purpose, alternative routing, authorization prerequisites, rendering fallback, return values ('extracted content and metadata'), a specific failure signal ('video_id is null'), and the destructive recapture behavior. Combined with existing annotations, an agent has what it needs to invoke this safely and 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 coverage is 100%, so the schema already fully documents url, render_mode, follow_links_depth, and include_screenshot. The description reinforces some schema details around rendering and screenshots but does not add meaningfully new parameter-level guidance, and it does not mention follow_links_depth at all. Baseline 3 is appropriate when the schema carries the parameter documentation.

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 opens with a specific verb and resource: 'Fetch an allowed webpage as Markdown and save it as a local corpus item.' It then explicitly distinguishes this tool from siblings by naming uoink_url for videos, uoink_x for post chains, and uoink_reddit_thread for comments. An agent can tell exactly what this tool does and which sibling to use instead.

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 states when to use this tool ('articles and documentation') and names the precise alternatives for other content types (videos, post chains, comments). It also says to use add_allowed_site 'only with user authorization,' giving a clear prerequisite and boundary condition. No inference is required to route correctly.

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