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

Beyond annotations, the description discloses the 60-second URL expiry, the exact HTTP request shape, path/header parameter mapping, and the requirement to verify downloaded bytes against the returned content digest. It also states that the immutable artifact reference is the only authority, adding meaningful behavioral 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?

Four sentences, all load-bearing: purpose, HTTP/MCP argument mapping, expiry, and integrity verification. The most important information is front-loaded and there is no 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 two-parameter tool with an output schema, the description covers the applicable artifact scope, URL lifetime, invocation mechanics, and verification expectations. Nothing essential is left to inference for an agent to call this tool correctly.

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 schema description coverage at 0%, the description must compensate. It usefully maps artifact_ref to a URL path parameter and says to relay it unchanged, and maps idempotency_key to the Idempotency-Key header. However, it does not explain the idempotency key's generation or deduplication semantics beyond that mapping.

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 opens with a specific verb and resource: it returns an idempotent, short-lived download URL for one verified artifact, explicitly including result artifacts named by a succeeded invocation's output_artifact. This distinguishes it clearly from the sibling invocation, offer, and inbox tools, none of which mint download access.

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 gives clear selection context by scoping the tool to verified artifacts the service holds, including invocation result artifacts. It does not explicitly name alternatives or say when not to use it, but no sibling tool serves the same purpose.

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