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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the description's job is to add operational context, which it does by disclosing the pricing basis (monthly USD list prices) and the workload-gated filtering of burstable/confidential SKUs. No rate limits or result-cap behavior beyond what the schema's max_results already carries.

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?

Two sentences, no waste, and the core capability plus its price output are front-loaded before the filtering caveat. Every clause carries information the agent needs.

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?

An output schema exists so return values need no explanation, and all ten parameters are schema-documented. The description supplies the purpose, price basis, and inclusion semantics an agent needs; only explicit sibling routing is absent.

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 ten parameters, including the enum semantics for workload and sort and the default for region. The description adds only the pricing basis (list vs. negotiated) and reinforces the workload gating, which is marginal over the structured fields.

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 (find Azure VM sizes) plus the defining output constraint: cheapest sizes meeting vCPU/memory/workload requirements with monthly USD list prices. This separates it from get_vm_size (single size lookup) and estimate_vm_cost (cost estimation for a known config), though it never names those siblings explicitly.

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 a real inclusion rule: burstable and confidential families are returned only when that workload is explicitly requested, which tells the agent when results will and will not contain those SKUs. It stops short of naming alternatives or stating when to reach for estimate_vm_cost instead.

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