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

With no annotations, the description carries the full burden. "Without a browser" usefully discloses that the page is fetched as static HTML with no JS rendering, but it says nothing about network fetch behavior, redirect handling, timeouts/rate limits, or what happens on non-HTML or error responses.

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?

Two sentences, front-loaded with the verb and resource, then the field inventory, then the usage clause. No filler; every clause carries signal.

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 single-parameter read tool with no annotations or output schema, the field enumeration effectively doubles as return documentation, which is the key need. Minor gaps remain around failure modes and whether redirects are followed, but an agent can call this correctly as written.

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 the single required parameter is already documented as "URL or bare domain." The description adds no syntax, normalization, or scheme-handling detail beyond that, so baseline 3 applies.

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?

Uses a specific verb ("Extract") with a precisely scoped resource (on-page SEO signals from a URL) and enumerates the exact fields returned, so the agent knows the tool's boundary versus siblings like security_headers or robots_txt without reading the schema.

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?

"Use for quick SEO triage without a browser" gives a situational hint, but it never names alternatives (e.g., when to prefer site_audit for a full crawl) or states exclusions. Usage is implied rather than routed.

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