Fetch a URL and fingerprint its likely tech stack from response headers (server, x-powered-by, x-generator) and HTML markers (generator meta tag, framework/CMS-specific script or class patterns). Best-effort — not exhaustive, no additional paths are probed.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | The URL to fingerprint |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral disclosure burden and does well: it specifies the data sources (headers, HTML markers), states it is best-effort and not exhaustive, and explicitly says no additional paths are probed. It does not cover redirects, timeouts, or output shape, but for a simple read-only fetch tool the disclosure is strong.
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 sentences, front-loads the core action, then efficiently lists the fingerprinting sources and the key limitation. Every sentence adds value with no redundancy or 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?
The tool is simple (one parameter, no output schema) and the description covers the process, sources, and best-effort nature. It does not detail the exact return format or failure behavior, but the purpose and outcome are clear enough for a competent agent to invoke it 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?
The schema already documents the only parameter 'url' with 100% coverage, so the baseline applies. The description adds that the URL is fetched and used for fingerprinting, but does not add URL format requirements or edge-case semantics beyond what the schema provides.
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 verb ('Fetch') and resource ('a URL') and clearly defines the tool's purpose: fingerprinting a likely tech stack from response headers and HTML markers. This distinguishes it from sibling tools like security_headers_audit or url_to_markdown, which have different objectives.
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 no explicit guidance on when to use this tool instead of a sibling, nor does it name alternative tools or exclusion criteria. The 'best-effort' caveat is a limitation, not a usage guideline, so an agent is left to infer when this tool is appropriate.
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.
Many tools audit overlapping site signals (seo_audit vs structured_data_extract vs tech_stack_fingerprint; page_performance_check vs pagespeed_insights; ssl_cert_check vs ssl_labs_grade; broken_link_check vs sitemap_url_validator), so an agent could initially pick the wrong one. Descriptions usually clarify the distinction, but the boundaries are not always obvious.
Most names follow a snake_case target+operation pattern (ssl_cert_check, email_deliverability_check), but check_open_ports and check_robots_sitemap reverse the order, and the action suffixes vary widely (check, audit, validate, lookup, extract, grade, report, insights). Still readable, but not a single predictable convention.
At 29 tools, the server is above the 25-tool threshold and feels like an undifferentiated grab bag of single-purpose audits rather than a tightly scoped toolkit. Many checks could be consolidated (e.g. the separate SSL and performance tools, or domain_report versus its component checks).
For a web/domain/email/security diagnostics toolbelt, the coverage is unusually broad: DNS, TLS, email, SEO, structured data, vulnerabilities, ports, redirects, and more are all represented. Minor gaps exist (no generic HTTP request/debug tool, no zone-transfer or full WHOIS history), but agents can accomplish most diagnostic workflows without hitting dead ends.