web_fetch

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

Annotations already cover read-only, idempotent, non-destructive, and open-world hints. The description adds valuable context: HTML is stripped, no permission required, and pages must be public. This goes beyond annotation coverage, though it does not mention failure behavior or rate limits, which keeps it at a 4.

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 sentences, no fluff. The first sentence states the core function and key transformations (HTML stripped), the second gives usage cases and constraints. Every word earns its place.

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 simple fetch tool with complete schema and annotations, the description covers purpose, usage, and behavioral traits. The return type (plain text) is implicit from the description, and no output schema is needed. It is fully adequate for an agent to select and invoke 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 description coverage is 100%, with both parameters well documented (URL with https assumption, max_chars with range). The description adds no parameter-specific details beyond what the schema provides, so baseline 3 is appropriate.

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?

Clearly states the specific verb 'Fetch' and resource 'plain-text content of any public web page'. Distinguishes from siblings by noting no browser is needed, separating it from browser_open_url, and from web_search by focusing on fetching a specific URL versus 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?

Provides explicit usage context: 'Use this to read articles, docs, pricing pages, or any URL the user mentions.' This implies when to use, and 'No browser needed' hints at an alternative. However, it does not explicitly name alternative tools or state when not to use, falling short of a 5.

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