Compare two libraries

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

Annotations already declare the operation read-only and non-destructive. The description adds useful non-obvious context by specifying the output categories (added, removed, modified) and the file-type restriction, which helps the agent predict the tool's behavior.

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: purpose first, then output detail and constraint. Every sentence adds information without redundancy or filler.

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?

For a simple read-only comparison with two well-documented parameters, the description covers the core invocation requirements and output categories. It does not detail the exact diff report format or what counts as 'modified', but no output schema exists and the core behavior is clear.

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 already documents filepath_a as base/old and filepath_b as new/changed, and the description adds the cross-parameter constraint that both files must share the same extension type. This is meaningful semantic value beyond the schema.

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 the action (compare), the exact resource (two Altium library files), and the high-level result (report added/removed/modified components). The 'library files' phrasing distinguishes it from the sibling compare_components, which targets individual components.

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?

Provides a clear prerequisite: both inputs must be the same type (.PcbLib or .SchLib). It does not explicitly say when to prefer this over sibling tools like compare_components, so it stops short of full alternative guidance.

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