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

Beyond readOnlyHint/idempotentHint annotations, description discloses HEAD request with GET fallback, redirect-following with safety checks, determinism, and pricing ($0.002 via x402). No contradictions.

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?

Three sentences: behavior, key attributes (deterministic, no download), and pricing. Front-loaded with essential info, no fluff.

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 annotations (readOnly, idempotent, non-destructive) and presence of output schema, description sufficiently covers behavior, parameters, and return fields (up/down, status, latency, redirect chain, headers). Complete for purpose.

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?

Single parameter 'url' with schema description already clear. Description adds example URL but doesn't provide new info. Schema coverage is 100%, 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?

Description clearly states it's an uptime/health probe for public URLs, sending HEAD requests, following redirects, and returning status/latency/headers. It specifies it's a monitoring probe for schedule calls, distinguishing it from scraping or other tools.

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?

Description explains when to use (uptime checks for public URLs, deterministic, no page download), implying it's not for full page analysis. It doesn't explicitly name alternatives like get_scrape, but the context from siblings makes it clear.

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