fetch_url

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

Given no annotations, the description fully details behavior: returns page title, readable text, outbound links, next_cursor on truncation, refusal of certain URLs, and warns that content is untrusted. This is comprehensive for a read-only 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?

Three purposeful sentences with no waste. The first sentence states usage and purpose immediately. Each subsequent sentence adds essential behavioral info. Structure is efficient and front-loaded.

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?

Despite no output schema, the description covers key return fields (title, text, links, cursor) and constraints. Minor gap: no explicit mention of error behavior for invalid URLs/IDs, but overall it is sufficient for a tool with four parameters and good annotations.

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%, and the description adds value: explains preferred parameter (id_or_url), clarifies cursor and max_chars semantics (soft cap), and notes that URL is deprecated. This goes beyond the schema descriptions.

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 the tool's purpose: to read content of a search result after a search. It specifies the verb 'read' and the resource 'actual content of a result', and distinguishes from sibling web_search by indicating it should be used after a search.

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?

Provides explicit context: 'Use this after a search' and 'Pass either a search result id (preferred) or a full http(s) URL.' It implies when to use (after search) and excludes non-http(s) and private hosts. However, it does not explicitly mention alternatives beyond the sibling tool name.

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