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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuine context by naming the upstream source ('Azure Retail Prices API for that region and SKU'), implying live external data and possible availability gaps by region/SKU. It does not disclose failure behavior for unknown SKUs, caching, or how reserved/spot rates are surfaced given no parameter selects them.

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, front-loaded with the core purpose, but the parenthetical pricing-mode list and the opaque 'Vietnis price and VND' clause consume space without adding actionable meaning. Tightening toward what the tool takes and returns would improve it.

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?

There is no output schema, and the description does a fair job summarizing what comes back (list price, monthly cost for N machines, converted VND figure). Given six parameters and an external data source, the missing pieces are the unselected pricing modes and the undocumented os/lang/hours parameters, but the essential shape is conveyed.

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?

With only 33% schema description coverage, the description needs to carry parameter meaning, and it only partially does: it clarifies that cost is computed for N machines (the count parameter). The os, lang, and hours_per_month parameters are unexplained in both description and schema, and the description advertises 1-/3-year reserved and spot pricing even though no parameter exists to select a pricing mode, leaving an agent unable to reconcile inputs with outputs.

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 names a specific verb-and-resource pairing ('Live Azure list price for a VM size in a specific Azure region') and enumerates the pricing dimensions returned, which separates it from estimate_gcp_vm. The unexplained phrase 'the Vietnis price and VND' introduces ambiguity about an extra output, and no sibling tool is named explicitly, keeping it below a 5.

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 by the listed outputs: an agent can infer this is the single-VM-size pricing call, distinct from compare_azure_regions or recommend_cloud_region. There is no explicit 'use this when…' statement, no exclusions, and no guidance on which sibling to pick for multi-region comparison.

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