web_search

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds useful behavioral context beyond this: it specifies the search engine (DuckDuckGo), the output fields (title, URL, snippet), and that no API key or browser permission is required. This exceeds the baseline for annotation-covered tools.

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 two concise sentences. The first sentence immediately states the core function and output. The second sentence provides practical facts (no API key, no permission) and a pointer to web_fetch. Every sentence adds value with no filler.

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 search tool, the description is complete: it tells what the tool returns (top N results with fields), notes the underlying engine, mentions constraints (no API key, no permission), and gives a follow-up action (combine with web_fetch). Despite no output schema, the description covers the return semantics adequately.

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%, so the description does not need to compensate. The description briefly touches on num_results via 'top N results' but does not add new meaning beyond what the schema already provides for query and num_results. 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?

The description uses a specific action verb ('Search') and identifies the resource ('the web'), plus specifies the engine (DuckDuckGo) and return format (title, URL, snippet). It clearly distinguishes itself from siblings like web_fetch by noting it returns search results rather than full content.

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 gives clear usage context ('Search the web', 'No API key', 'No browser permission required') and explicitly mentions combining with web_fetch for full content. However, it doesn't explicitly state when to prefer other tools (e.g., browser_open_url) or provide an exclusion criteria, so it stops 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.