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

Annotations already indicate a non-read-only, open-world, non-idempotent operation. The description adds valuable context: it downloads from a URL, submits to an external service, optionally waits, and rejects private-network URLs and embedded credentials. It does not contradict annotations and provides useful behavioral details beyond them.

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?

The description is a single, front-loaded sentence that efficiently covers the workflow and key constraints. It is dense but well-organized, with no redundant information.

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?

Given nine parameters, an output schema, and annotations, the description covers the essential flow and security constraints but fails to explain most optional parameters. It is adequate for an agent to invoke the tool using defaults, but incomplete for leveraging the full parameter set.

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%, so the description must compensate. It only clarifies 'converter' (as a slug), 'source_url' (URL), and 'wait_for_completion' (optional wait). The remaining six parameters (width, height, quality, strip_metadata, timeout_seconds, background_color) are not mentioned at all, leaving significant gaps.

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 states a specific verb and resource: download a spreadsheet URL, submit it to XLSX.now with a converter slug, and optionally wait. It clearly conveys the core action and process, though it does not explicitly differentiate from siblings (which are not direct alternatives).

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: use this tool to convert a spreadsheet from a URL, with an option to wait for the result. There is no explicit guidance on when to use this versus polling via get_conversion_status, nor are any exclusions or prerequisites stated beyond the URL security constraints.

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