MCP Web Tools

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the search engine (DuckDuckGo) and return format, but fails to disclose critical traits like rate limits, authentication needs, error handling, or whether it's a read-only operation. For a tool with no annotations, this leaves significant gaps in understanding its behavior and constraints.

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 front-loaded and highly concise, consisting of two sentences that efficiently convey the tool's purpose and output. Every sentence earns its place by providing essential information without redundancy or unnecessary details, making it easy for an agent to quickly grasp the tool's function.

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 moderate complexity (3 parameters, no output schema, no annotations), the description is minimally adequate. It covers the basic purpose and output but lacks details on behavioral traits, error cases, or integration with siblings. Without annotations or output schema, more context on limitations or usage patterns would improve completeness for agent decision-making.

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?

The schema description coverage is 100%, so the schema already documents all parameters (query, max_results, region) with descriptions and defaults. The description does not add any meaning beyond what the schema provides, such as examples or usage tips for parameters. Baseline 3 is appropriate as the schema handles the heavy lifting, but no extra value is added.

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 specific action ('Search the web using DuckDuckGo') and resource ('web'), distinguishing it from sibling 'web_fetch' which likely fetches specific URLs rather than performing searches. It explicitly mentions what it returns ('list of search results with titles, URLs, and snippets'), making the purpose unambiguous and distinct.

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 implies usage for web searches but does not explicitly state when to use this tool versus the sibling 'web_fetch' or other alternatives. It provides basic context (searching the web) but lacks guidance on exclusions, prerequisites, or specific scenarios where this tool is preferred over others, leaving some ambiguity for the agent.

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