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

Adds substantial behavior beyond the readOnly/idempotent/non-destructive annotations: 256 KB payload limit, line-numbered errors on malformed input, safe-YAML-subset restriction (no anchors/tags), formula-injection guard, and per-call pricing/payment requirements. Missing only a statement of what the returned value looks like, which matters since there is no output 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?

Purpose and format list are front-loaded and every clause carries information; the options digest is dense but scannable. The pricing/HTTPS-endpoint sentence is operational rather than descriptive but still earns its place for an agent deciding whether it can call.

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?

Covers input constraints, supported formats, edge-case semantics, error behavior, and cost — enough to invoke correctly. The notable gap is return-value shape (string vs object, how nested/flattened output is packaged), which the absent output schema leaves unaddressed.

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 coverage is 100%, so the baseline is 3, but the description goes further by explaining the semantics of options: flattening produces dotted CSV columns, XML attributes surface as @keys, repeated elements become arrays, and CSV header/delimiter detection applies. That is meaningful behavior the schema only names.

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?

Opens with a specific verb and resource ("Convert data") plus the full set of target formats and auto-detection of the source. An agent can distinguish this from siblings like json_repair or schema_validate without opening the schema.

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 'in one call (auto-detects the input format)' and the mention of what the tool handles, but there is no explicit when-to-use/when-not guidance and no routing away from near-neighbors such as json_repair or html_to_markdown.

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