validate

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the tool's safety and non-modifying nature are known. The description adds 'via the family's backing server,' which is minor but not critical. It does not elaborate on potential side effects (none expected) or performance characteristics, but given the annotation coverage, the description adds adequate context.

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?

The description is a single sentence of 15 words, front-loaded with the verb 'validate.' It contains no filler, tautology, or redundancy. Every word contributes to defining the tool's core purpose.

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 has only 2 well-described parameters, an output schema (not shown but exists), and no nested objects, the description sufficiently covers the main operation. It does not mention output format or error handling, but the output schema is expected to fill that gap. The description is complete enough for an agent to understand the tool's role within the sibling toolset.

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 baseline is 3. The tool-level description does not describe parameters; however, the parameter descriptions in the schema are detailed (e.g., records lists example fields for pain.001, message_type explains versioning). The tool description adds no additional semantics beyond what the schema already provides.

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 clearly states the action ('validate records'), the resource ('for a message type against its JSON Schema'), and the mechanism ('via the family's backing server'). It distinguishes from sibling tools like describe (which returns the schema) and parse (which handles different operations).The verb+resource combination is specific and unambiguous.

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 implies the primary use case—validating records against a schema—and provides context (backing server). While it does not explicitly state when not to use this tool or compare with alternatives, the context is clear enough for an AI agent to infer appropriate usage. A more explicit exclusion (e.g., 'for schema retrieval use describe') would elevate to a 5.

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