page_metadata

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

With no annotations, the description carries the full burden. It does disclose two important traits: a fixed 0.002 USDC charge on Base mainnet and automatic payment via the wallet in PAYER_PRIVATE_KEY, which tells the agent about cost and auth setup. It says nothing about failure modes on unreachable pages, redirect handling, or caching, leaving real behavioral gaps for a network-fetching tool.

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, zero filler, with the capability stated first and the cost/payment fact second. Every clause earns its place.

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?

No output schema exists, so the enumeration of returned fields is genuinely necessary and present. Cost and payment mechanism are covered. Minor remaining gap: no mention of what happens when a page cannot be fetched or when the wallet lacks funds.

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% for the single 'url' parameter, so the schema already carries the semantics. The description adds no constraint, format, or scope detail beyond what the schema's example provides, so the baseline of 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?

The description uses a specific verb-and-resource ('Fetch page metadata') and enumerates the exact fields returned (title, description, canonical, Open Graph/Twitter tags, icons, structured data types). It does not, however, distinguish itself from siblings like page_reader or website_intelligence, which an agent could reasonably confuse with metadata extraction.

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?

There is no statement of when to choose this over page_reader or website_intelligence, nor any exclusions. The only usage-relevant signal is the per-call cost, which implies 'use sparingly' but never says so explicitly.

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