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

Annotations already declare openWorldHint=true, readOnlyHint=false, and non-idempotent, and the description adds a real behavioral constraint beyond them: private-network URLs and embedded URL credentials are rejected. It still omits what happens if the wait times out and whether a pending job is left behind, so it is not fully transparent.

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 front-loaded sentences that describe the pipeline first and the rejection constraint second, with no filler. Every clause carries information an agent needs.

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?

An output schema exists so return values need no explanation, but for a 9-parameter, non-idempotent open-world tool the description should at least cover the resize/quality/metadata options and the async polling path. The security constraint is the only substantive addition.

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% across 9 parameters, so the description carries the full burden and largely fails: only source_url and converter (via 'converter slug') and wait_for_completion (via 'optionally wait') are hinted at. Width, height, quality, strip_metadata, timeout_seconds, and background_color get no meaning at all, and no accepted converter slugs are listed.

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 gives a concrete verb chain (download, submit, optionally wait) tied to a named service and a specific input, so the agent knows exactly what the tool does. It does not name siblings such as get_conversion_status, though 'optionally wait for the result' implies that async path exists.

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?

Usage is implied by 'optionally wait for the result', but the description never states when to set wait_for_completion=false or that the agent should then poll get_conversion_status, nor when to prefer this tool over re-using an existing job. Adequate but leaves the async workflow to inference.

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