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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them by disclosing that rows are transient and not persisted, that referential and lifecycle integrity are NOT checked, and that confidential data is prohibited. Those are non-obvious behavioral traits an agent could not infer from the annotations. No contradiction with readOnlyHint=true.

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 tight sentences, front-loaded with the core action and constraint; each sentence adds a distinct limit or caveat. No filler, though the 'one fixed Waypoint schema' phrasing introduces avoidable ambiguity.

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?

With no output schema, the description should hint at what a validation result contains (errors, row indices, pass/fail), which it omits. It is otherwise adequate about scope and limits for a two-parameter read-only tool.

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 0%, so the description carries the burden, yet it only restates the 20-row cap (already in maxItems) and says nothing about what the three dataset enum values mean or how they relate to the validation schema. The 'one fixed schema' wording even obscures the multi-dataset parameter.

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?

Specific verb (Validate) plus resource (synthetic example rows) and scope (up to 20, against a schema). It is easily distinguishable from get_resource and search_reference. The phrase 'one fixed Waypoint schema' is slightly at odds with the dataset enum of three values, which blurs the purpose a little.

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 real usage boundaries: max 20 rows, transient/non-stored, no foreign-key or lifecycle checks, and a confidentiality caveat. However it never names an alternative tool or states positively when to prefer this over sibling lookups.

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