lib_diff_libraries

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

With no annotations, the description carries the full load: it does disclose that both inputs are files (SchLib), that the operation is a non-mutating comparison, and what categories of difference are reported. It does not state permission requirements, what happens if a path is invalid or the library is open in the editor, or whether comparisons are name-based or content-based — meaningful gaps for a tool with zero annotation coverage.

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?

Front-loaded with the purpose sentence and the three diff categories, which is the right ordering. The explicit 'Args' and 'Returns' blocks are somewhat redundant — the return keys are already documented by the output schema and the arg names repeat the schema — but the total length is still modest.

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 two-file read-only comparison with an output schema present, the description covers purpose, inputs, and result shape adequately. The remaining omission is failure behavior (missing file, unreadable library) and whether both libraries must be closed in the editor, which an agent would need before calling.

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, and it does: both parameters are documented as full filesystem paths to SchLib files, which is more than the bare 'Library A' / 'Library B' titles provide. It stops short of specifying path-format or relative-vs-absolute rules.

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 uses a specific verb and resource ('Compare two schematic libraries') and states exactly what the result contains (components only in A, only in B, or shared). No sibling tool performs library diffing, so the operation is inherently distinguishable, though the description never names a boundary against nearby tools like lib_search or app_update_from_libraries.

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 only implied by the verb 'compare' — an agent can infer this is a pre-sync/pre-merge check, but the description never states when to choose this over app_update_from_libraries or proj_get_differences. There are no prerequisites or exclusions listed.

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