Web search

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

Annotations declare readOnlyHint=true and openWorldHint=true, which aligns with the description (read-only, returns links, nothing fetched). The description adds valuable context beyond annotations: explains the dual backend (SearXNG when SEARXNG_URL set, otherwise stealth-browser rendered page) and clarifies no content is fetched until requested. Confirms the lazy-fetch behavior without contradiction.

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?

Well-structured with a clear first line stating the core purpose, followed by a 'Not for' exclusion line, a usage-recommendation paragraph, and a backend-detail sentence. Every sentence earns its place; nothing is redundant or padded. Approximately 90 words for a tool that does meaningful work.

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 output schema exists, return values are covered structurally. The description covers purpose, exclusions, alternative tools, workflow recommendation, and backend behavior. For a 2-param read-only search tool, this is fully complete—the agent has everything needed 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 coverage is 100% and both parameters (query, limit) are described in the schema itself. The description mentions the tool returns ranked hits but adds nothing about parameter syntax or semantics beyond schema. Baseline 3 is appropriate given full schema coverage; description adds minimal extra parameter value but the schema fully documents them.

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?

Clear verb+resource ('Search the web') with explicit output format (ranked hits: title, url, snippet, engine). Strongly distinguishes from siblings by explicitly stating what it is NOT for (returning page content vs links).

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?

Excellent when/when-not guidance: explicitly says use read_url for one known URL, research when you want the answer rather than links. Also gives a concrete workflow pattern: find pages, then pass URLs to read_url. This is exactly the differentiation agents need among the three sibling search-ish tools.

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