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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, and the description adds substantial context on top: the destination fallback chain, the meaning of all three status values, the needs_interaction flag, and the critical distinction that no status blocks a handoff but merely predicts whether autonomous completion can work. No contradiction with 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?

Purpose is front-loaded and the three sentences are dense, each covering a distinct concern: purpose, address resolution, then status/needs_interaction semantics. Minor verbosity in the status explanation ('however its badge reads') and slight redundancy between requires_escalation and the needs_interaction sentence keep it just short of a 5.

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?

Given the tool's complexity — 7 parameters, an address-resolution chain, a three-valued status enum with subtle operational implications — the description covers all non-obvious semantics an agent needs to invoke it correctly. An output schema exists, so return-value details need not be spelled out in prose.

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%, so the baseline is 3. The description adds value beyond the per-parameter descriptions by specifying the full destination precedence chain (agent default → linked org default → country override), which ties agent_id, country, region, and postal_code together in a way no individual schema description does.

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 first clause states a specific verb and resource: 'Non-committing checkout probe for shipping ETA/cost.' It clearly differentiates from siblings like supply_search/supply_details (find and detail offers) and order_execute (commits) by framing this as a probe that does not commit.

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 conveys clear usage context: this is the pre-commit estimate probe, and it explains the destination resolution order (agent default, then org default, then country override). However, it never names alternatives or states explicit when-not-to-use conditions, so the agent must infer the contrast with order_execute and supply_details on its own.

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