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

Annotations already declare readOnly/openWorld/non-destructive, so the bar is lower, and the description still adds real behavioral detail: unmasked phone, email and links (versus masking in search), verification provenance, expiry, and availability of your own beacon across lifecycle states. It omits what happens on an unknown, expired or unauthorized id, which is the main remaining gap for an open-world read.

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, all load-bearing, with the core action and the id source front-loaded. The first sentence carries a heavy enumerated payload, which makes it dense but not wasteful.

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, so the description properly enumerates the return payload (words, contact details, location, expiry, verification checks) and lifecycle scope. Only failure and not-found behavior is left unspecified, a minor gap for a single-id lookup.

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 parameter's schema description already explains it is the id from the Link line, so the description merely echoes that framing. Baseline 3 is appropriate; no additional format or sourcing guidance is added beyond what the schema states.

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 with scope: "Read one beacon by the id at the end of its Link line." It also implicitly distinguishes itself from the sibling search_beacons by noting that search shows contact details masked while this tool returns them, so an agent can choose without opening either 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?

Gives an explicit trigger: "Use it before messaging or calling, to see the latest version," plus scope guidance that your own beacon is readable while being checked or after it closed. It stops short of an explicit when-not or a direct pointer to search_beacons for listing multiple beacons.

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