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

Beyond the readOnly/idempotent annotations, the description discloses two additive behaviors: the tool never executes or fetches the target request, and the optional economics parameter yields proceed/abort advice based on expected waste versus the $0.001 check price. These are meaningful behavioral facts not derivable from 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, each earning its place: purpose, non-execution plus usage trigger, and economics behavior. The verb-resource-object is front-loaded in the first clause, and nothing repeats schema content or annotations. Zero filler.

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 3-parameter tool with an output schema, safety annotations, and well-documented nested fields, the description plus structured data covers everything an agent needs for a successful call. The economics versioning (V0.1 vs V0.2) lives in the schema, and return values are covered by the output schema. Only minor edge behavior, like handling of a malformed schema, is unaddressed.

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?

The schema already documents all parameters well at 67% coverage, including nested request fields and the economics object's full structure. The description adds only the proceed/abort decision framing for economics, which is a modest but genuine increment over the schema's 'cost context' phrasing. A 3 baseline is fair since the schema carries most of the load.

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: 'Validate an HTTP API request body against a supplied JSON Schema.' It additionally draws a hard boundary with 'This tool does not execute the request,' making its non-executing role unmistakable and separating it from any send/execute tool even without naming the sibling.

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 explicit when-to-use direction: 'Use it when an agent needs to determine whether a proposed JSON body satisfies its expected schema' and frames it as a pre-send validation step. However, it never names preflight_tool_call as an alternative nor states when not to use this tool, so it stops at clear context without exclusions.

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