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

Annotations already mark it as read-only, idempotent, and non-destructive Button. The description adds non-obvious behavior: the URL expires and the caller must fetch it themselves. This is valuable beyond the structured annotations, though it doesn't specify the exact expiry duration.

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?

Five concise sentences, each carrying information: what it does, how to consume it, an example, return shape, cross-reference, and a cheaper alternative. Front-loaded with the core action and constraints.

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?

Despite having no output schema, the description enumerates the returned fields and summarizes the mechanics (short-lived URL, plain GET, no headers). It also addresses cross-tool data flow (run_artifacts) and alternative tool selection (query_run). An agent has everything needed to call it 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?

The schema documents parameter names and types at 0% description coverage, and the description compensates with a concrete JSON example plus the provenance clue that artifact_id values come from run_artifacts. It doesn't fully explain run_id's source, but the example plus schema types make it usable.

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:

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 explicit usage context: fetch the URL with a plain GET, no headers, it is short-lived; and explicitly says not to use this for reading a few rows, pointing to query_run as the cheaper alternative. It also tells where artifact IDs come from (run_artifacts), which eliminates a common caller mistake.

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