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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false), and the description adds real behavioral context: a callback within the hour during business hours, no cost to the homeowner, the consent prerequisite, and a return reference. It does not say what happens on failure or invalid ZIP, keeping it below 5.

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 is front-loaded and most sentences carry unique information. However, "A vetted local pro calls them back (a vetted local pro calls back within the hour during business hours)" is a redundant restatement that could be collapsed into one clause.

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?

For a 7-parameter mutating tool with no output schema, the description covers cost, latency, consent, return value, and sibling routing, which is close to complete. The gaps are failure behavior and whether repeat submissions create duplicate requests (relevant given idempotentHint=false).

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 all 7 parameters including format hints for zip and phone. The description's only parameter-relevant addition is the geographic framing of the ZIP, which is marginal. 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 ("Book windshield replacement"), plus geographic scope (Oklahoma City area), and is clearly distinguishable from check_service_area (area validation) and get_service_info (informational). An agent can route without opening any 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?

Explicitly routes the agent to the sibling: "Check the ZIP with check_service_area first if unsure," and states a precondition (a real person who asked, with their consent). It lacks explicit when-not-to-use guidance or an alternative booking path, so it falls short of a 5.

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