Download artifact

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds real behavioral value beyond that: it discloses the return shape and, more importantly, that the tool does not stream bytes but hands back a signed URL that must be followed, which an agent could not infer from the schema.

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?

Two tight sentences that lead with the return value and then the required follow-up action. The trailing 'Read operation.' is mildly redundant against readOnlyHint=true, but it costs almost nothing.

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 carries the burden of explaining returns and does so (URL, filename, media type, size), plus the follow-the-URL step. Combined with fully documented parameters and annotations, an agent has enough to call this correctly; only sibling differentiation 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 all four parameters (account, version_id, artifact_id, output_file) are already documented, including version defaulting and the private output_file requirement. The description adds no parameter-level detail, so the baseline 3 applies.

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?

States a specific verb and resource ('Returns a signed download URL for an artifact') and enumerates what comes back (filename, media type, size), so the agent knows exactly what the call yields. It does not, however, differentiate itself from the nearby download_file / download_files / download_skill_file siblings, leaving the artifact-specific scope implicit.

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 instruction 'Follow `download_url` to fetch the file bytes' implies the intended two-step usage, which is genuinely useful. But there is no explicit guidance on when to pick this over download_file or download_files, and no mention of prerequisites or when-not-to-use.

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