Check the health status of a domain.
Returns the circuit breaker state: 'closed' (healthy), 'open' (failing),
or 'half_open' (testing recovery). Use this before batch operations to
avoid wasting time on domains that are down.
Args:
domain: The domain to check (e.g., 'example.com')
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses the circuit breaker states and their meanings ('closed', 'open', 'half_open'), which adds valuable context about what the tool returns and implies it is a read-only health check. It does not mention potential errors, but for this simple tool it is sufficient.
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 brief and front-loaded with the verb-resource statement. Each sentence adds value: what it does, what it returns, when to use it, and parameter explanation. No fluff or redundancy.
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?
The tool is simple and the description covers the core behavior, usage context, and return value interpretation. An output schema exists, so detailed return value structure is already provided. However, it does not mention error handling or domain format edge cases, leaving a slight gap for a production tool.
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 has no description for the 'domain' parameter (0% coverage). The description compensates by including an Args section that explains the parameter and gives an example format ('example.com'). This adds meaning beyond the bare schema definition.
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 'Check the health status of a domain' with a specific verb and resource. It distinguishes itself from sibling tools like cache_stats and fetch_url by focusing on domain health, not caching or fetching.
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?
It explicitly says 'Use this before batch operations to avoid wasting time on domains that are down,' providing a concrete use case. However, it does not mention when not to use it or point to specific alternatives, so it falls 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.
Add one secure layer between your agents and this server.
fetch_url and fetch_markdown both fetch URLs, but fetch_url returns raw HTML+markdown while fetch_markdown returns only markdown, which is a clear distinction. check_domain, cache_stats, and clear_cache are all distinct. The overlap is minor and well-handled by descriptions.
Most tools use a verb_noun pattern: check_domain, clear_cache, fetch_markdown, fetch_url. cache_stats deviates slightly, being a noun_noun phrase, but it's still clear and consistent enough.
With 5 tools, the set is well-scoped for a fetch/cache utility. Each tool serves a distinct purpose without redundancy or bloat.
The tool surface covers the core lifecycle: fetching with two output formats, cache inspection, cache clearing, and domain health checks. No obvious gaps for the stated purpose of reliable fetching with caching and circuit breaking.