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

Annotations already declare readOnly, idempotent, closed-world, non-destructive behavior, so the safety bar is low. The description usefully adds fallback behavior ('Returns a general guide when no exact match exists'), but says nothing about how ambiguous matches are resolved or what a general guide looks like.

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 with no filler; the core action is front-loaded and the fallback behavior follows. Slightly terse given the open questions it leaves, but nothing is wasted.

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 three optional parameters, no required fields, and no output schema, the definition should clarify at minimum what happens with empty input and how the standard parameter affects matching. The fallback sentence covers one edge case, but the parameter-interaction and no-input cases remain 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 description coverage is only 33%, so the description needs to compensate but does not. It never mentions code, message, or standard, nor how they combine (e.g., whether standard narrows the match, or what happens if all three are omitted since none are required).

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 names a specific verb and resource ('Match an XML/XSD or invoice error code or message to a ... guide and explanation'), which is far more informative than the title alone. It does not explicitly distinguish itself from the sibling search_xsdhub_guides, but the matching/lookup framing makes its role reasonably clear.

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: call this when you have a validation error to interpret. There is no explicit statement of when to prefer this over search_xsdhub_guides or the validate_* tools, and no mention of prerequisites or ordering relative to validation.

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