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

Annotations cover read-only, idempotency and open-world scope, and the description still adds non-obvious behavior: data is read live from PulseWatch, untracked names do not abort the call, and the call is not charged when nothing is tracked or all lookups fail. Billing terms (flat $0.05 USDC via x402, payment in _meta["x402/payment"]) are disclosed in a way annotations never could.

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?

Purpose and scope are front-loaded in the first clause, with sibling routing and caveats following. The final sentence chains read-only, price, and payment metadata into one semicolon-separated run, which is dense but each clause carries distinct information.

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?

With no output schema, the description still conveys what comes back (per-vendor status plus a not-operational list), that data is live, and how partial failures and billing behave. Nothing material for a correct invocation is missing.

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 schema already documents 1-25 entries and that entries may be names, slugs or domains. The description only restates the 25 cap and adds that unmatched names are reported, without clarifying slug vs domain formatting, so it sits at the baseline for a fully documented parameter.

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 (check status of up to 25 SaaS/cloud vendors in one call), the question it answers ("is my stack down?"), and the returned shape (per-vendor status plus a list of non-operational ones). It also names the sibling vendor_status and the condition separating them.

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?

Explicit when-to-use framing ("is my stack down?" aggregate checks) and an explicit alternative with a selection rule: use vendor_status for incident detail on a single vendor. It also pre-empts a common failure case by noting untracked names are reported rather than fatal.

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