Fetch URL

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

With no annotations, the description fully describes the multi-tier fallback behavior, special handling for certain content types, and session caching. It lacks mention of authentication, rate limits, or error handling, but still provides good transparency.

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 concise (approximately 100 words) and front-loaded with the main purpose. Each sentence adds value without redundancy.

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?

The description covers the core functionality, special cases, fallback chain, and caching. It does not detail error behavior or output format beyond 'clean markdown', but for a fetch tool this is reasonably complete.

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%, but the description adds meaning by explaining the tier fallback system, which gives context to the maxTier parameter. The description complements the schema well.

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 clearly states it fetches a URL and returns content as clean markdown, with specific handling for Twitter, YouTube, arXiv, and PDFs. It distinguishes from sibling tool 'search' by focusing on fetching a specific URL rather than searching.

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 implicitly guides usage by explaining the fallback chain and caching, but does not explicitly state when to use this vs. search or when not to use it. Given the sibling is 'search', the context is clear enough.

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