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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: data is 'reconciled from the phone system on every call' (indicating freshness/accuracy), and it explicitly discloses the 409 error condition when the hosted phone system is not set up. This goes beyond the annotations.

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 with no waste. The core purpose is front-loaded, followed by a data-freshness note and an error condition. Every sentence 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?

The tool has an output schema, so return values don't need explanation. The description covers purpose, data source, and a key error condition. It could mention pagination or rate limits, but for a simple read-only tool with one optional parameter, this is nearly complete.

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 description coverage is 100%, so the schema already documents the single business_id parameter. The description doesn't add parameter-specific details beyond what the schema provides, but with only one parameter and full coverage, the baseline 3 is appropriate.

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 clearly states the tool reads how calls ring on the business's hosted phone system, specifying the exact details it returns (which cells and desk phones ring, duration, after-hours routing to AI receptionist). It distinguishes itself from siblings like get_phone_system_status and update_phone_flow by focusing on the read-only flow behavior.

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?

The description implies when to use this tool: when you need to understand call routing behavior on the hosted phone system. It mentions the mirror of POST /api/v1/phone-system action=get_flow, which provides an API-level reference. However, it doesn't explicitly state when not to use it or name alternative tools for related but different queries (e.g., get_phone_system_status for overall system health).

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