beacon_fetch

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

With no annotations provided, the description fully takes on the burden of behavioral transparency. It discloses that it drops navigation/ads/boilerplate, returns plain text not HTML, truncates via max_chars, and returns None on fetch failure. These behavioral traits go well beyond the basic schema and give the agent a realistic expectation of the tool's behavior.

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 well-structured: a concise opening claim, followed by a brief detail on extraction, a note on return type, then a simple Args/Returns list. Every sentence contributes useful information, with zero redundancy. It is appropriately sized for the tool's complexity.

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?

Given the tool's simplicity (2 params, 1 required, no enums), the description is fully complete. It covers the purpose, behavior, parameters, return format, and failure case. The presence of an output schema is not strictly necessary because the description already states the return shape ('{"url", "title", "content"} or None').

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?

Since schema description coverage is 0%, the description must fully explain parameters. It does: url is specified as an http(s) URL, and max_chars is explained as a truncation limit to protect context budget with a default of 8000. This adds meaningful semantics that the bare schema properties ('url', 'max_chars') lack.

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?

Description states a specific verb ('Fetch a URL') and resource ('return its main readable text content'), clearly distinguishing it from the sibling beacon_search tool which searches rather than fetches. The first sentence is unambiguous about the tool's action and output.

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 clearly implies the tool is for retrieving URL content, which implicitly differentiates it from beacon_search. However, it does not explicitly state 'use this when you have a URL' or provide exclusions/alternatives, so it falls just short of a perfect score. The context is clear enough for an agent to infer the appropriate use case.

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