validate_instance

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

No annotations are supplied, so the description carries the burden; it usefully discloses the return shape (pass/fail, error count, classified errors). It does not say whether the check is read-only, what happens if check_compliance fails, or whether any files are written, leaving meaningful behavioral gaps.

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 the core action front-loaded and the output summarised second. No filler, though it is brief enough to leave gaps.

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?

It covers the action and the return value, which is good given there is no output schema. However, with no annotations and two sibling tools doing similar-sounding things, the definition lacks the routing and safety context an agent needs.

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 100% and each parameter (schema_path, instance_path, check_compliance) is documented there. The description adds nothing about parameter meaning or format, so the baseline 3 applies.

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 ('Validate an XML instance against its SDC4 XSD schema') and adds a return summary. Clear on its own, but it does not distinguish itself from the siblings validate_and_report and check_schema_compliance, which sound closely related.

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?

No indication of when to pick this over validate_and_report or check_schema_compliance, and no prerequisites or exclusions. The agent must infer the difference from names alone.

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