Validate without rendering

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

Annotations already declare readOnlyHint/idempotent/non-destructive, and the description adds genuinely new behavior: dry_run is forced true after local schema checks, no credits are consumed, nothing is queued, and the returned effective source/errors/warnings are described. It also warns that valid:true does not prove media reachability, credentials or appearance, which is exactly the caveat an agent needs before trusting the result.

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 terse sentences, front-loaded with the core action, then cost behavior, then return/caveat. No filler or repetition of schema content.

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 two-parameter validation tool with full schema coverage and no output schema, the description covers action, cost behavior, and the meaning and limits of the result. Only a brief pointer on when to prefer a real render over validation is missing.

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 account and the payload fields, and the baseline of 3 applies. The description adds one meaningful note that payload.dry_run is forced true, which reconciles the schema's disallowance of that field, but provides no additional per-parameter syntax.

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 the operation precisely: a single-provider v2 dry run that validates a render payload without rendering. It is clearly distinguishable from the batch siblings (submit_render_batch, preview_render_batch) and from create_legacy_render by the v2 framing, though it never names an alternative 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?

Cost and queue signals ('zero credits and no queue') imply this is the cheap pre-flight check to run before a real render, and the dry_run forcing clarifies you cannot accidentally trigger work. However there is no explicit when-to-use/when-not statement or named alternative such as create_render.

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