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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description still earns credit by adding two pieces of behavior an agent cannot get from annotations: the data is reconciled live, and a specific 409 failure mode exists when the hosted phone system isn't provisioned. It stops short of saying how to resolve that 409.

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 tight sentences: what it returns first, provenance second, error case last. No filler, no restatement of the title, and the most decision-relevant detail (what you get back) is front-loaded.

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 a rich annotation set, a documented single parameter, and an output schema handling return values, the description covers purpose, freshness, and the notable failure mode. The only gap is what the agent should do after a 409, which borders on usage guidance but would fully close the loop.

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?

There is one parameter and the schema already documents it at 100% coverage, including the conditional requirement ('required when the token can access multiple businesses'). The description adds no additional meaning about business_id, so this sits at the baseline for fully documented params.

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 ('Read') plus the resource and its scope: which cells/desk phones ring, ring duration in seconds, and after-hours routing. It even names the factual source of truth ('reconciled from the phone system'), so an agent knows exactly what data comes back and can distinguish it from update_phone_flow by the read-only framing.

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?

Usage is only implied: 'Read' signals a non-mutating inspection of the current configuration, which suggests it is the counterpart to update_phone_flow. There is no explicit 'use this when you need X, use update_phone_flow when you need Y,' and no guidance on what to do when the 409 (phone system not set up) is returned.

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