Add libraries

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

Goes well past the annotations by declaring 'NOT undoable' (a concrete reversibility statement), stating that already-loaded paths are reported rather than erroring, and naming the return payload (per-path results plus the new library list). This is consistent with destructiveHint=true and idempotentHint=true and adds real decision-relevant context.

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?

Three tight sentences with no filler, and the critical constraint ('NOT undoable') is placed early. Dense but every clause carries information an agent needs.

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 no output schema, the description compensates by summarizing the return shape, and it covers path format, undoability, and repeat-call behavior for a destructive single-parameter mutation. Only explicit sibling differentiation is missing.

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% (baseline 3), and the description adds meaning the schema lacks: '~/' expansion, that values are Mac-local absolute paths, and that .lcf library containers are also acceptable. That is genuine added semantics over the schema's single 'paths' description.

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?

Specific verb+resource ('Adds local libraries to the project and loads them') with the accepted input kinds spelled out (absolute folder paths or .lcf containers). It clearly distinguishes the operation from a plain read, but never names or contrasts the nearby siblings remove_libraries / reload_libraries / get_libraries, so the agent must infer which of the four library tools to pick.

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 rather than stated: the path-format rules and the 'alreadyLoaded' behavior tell the agent it is safe to re-run, but there is no explicit when-to-use-this-instead-of-X guidance despite three sibling library tools. Adequate but leaves the agent to infer the routing.

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