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

Goes well beyond the readOnly/idempotent annotations by disclosing the two operating modes: returning a priced x402 request URL (GET /software/eol, $0.002 per call) versus with a P0 bearer key executing the paid call and deducting the listed price. It also states that invalid input is refused before any charge, which is exactly the cost-safety information an agent needs before invoking.

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?

Front-loads the trigger and inputs, then the return shape, then payment mechanics and the authenticated shortcut — a sensible information order. It is dense rather than padded, though the long embedded purchase URL and the dual-mode explanation make it longer than typical; nothing is truly redundant.

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?

There is no output schema, and the description compensates by naming the returned fields (release cycle, EOL date, supported flag). It also covers the non-obvious operational concerns — pricing, auth header format, where to obtain a key, and fail-before-charge behavior — so an agent can call it correctly in either mode.

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%, so both parameters are already fully documented with patterns and examples. The description repeats the same examples (python, nodejs, ubuntu, 3.8.10) and adds no format, casing, or slug-resolution detail beyond the schema, 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?

States a specific verb and resource ("know if a software version is still supported") and enumerates exactly what comes back: release cycle, end-of-life date, supported flag. It names the product/version inputs and gives concrete product slugs, making it easy to distinguish from siblings like package_risk or vuln_cve.

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 when you must know if a software version is still supported" gives a clear triggering condition. It does not explicitly route the agent away from adjacent tools (vuln_cve, package_risk, site_snapshot) for overlapping questions, so the when-not guidance is implicit rather than stated.

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