Fetch a URL

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful output-shape context (markdown vs plain text conversion), but omits behaviors that matter for a web fetch: whether JavaScript-rendered pages are supported, rate limiting, robots/paywall handling, or error behavior on unreachable URLs.

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 short sentences with the action front-loaded and no redundancy. The trailing 'for analysis' is mild filler but does not bloat the definition.

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 must carry the return-shape burden; it partially does so by naming markdown/plain-text output, and the schema covers truncation. However, it says nothing about dynamic-page support or failure modes, which an agent needs to decide between this tool and cdp_navigate or firecrawl_scrape.

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 url, max_chars, and extract_mode are all already documented in the schema. The description echoes the markdown/plain-text choice that extract_mode encodes but adds no format, syntax, or default guidance beyond it. Baseline 3 applies when the schema does the heavy lifting.

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+resource ('Fetch a URL') and the transformation it performs ('extract readable content', 'converts HTML to markdown or plain text'). It is clear what the tool does, but it does not distinguish itself from siblings that also retrieve web content, such as navig_web_search, firecrawl_scrape, or cdp_navigate.

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?

There is no when-to-use guidance, no exclusions, and no mention of alternatives. The agent is left to infer that this is for fetching a known URL versus searching (navig_web_search) or rendering dynamic pages (cdp_navigate/firecrawl_scrape), which is exactly the ambiguity the description should resolve.

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