proj_libraries

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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), yet the description adds real value beyond them: it defines the '*' marker semantic, states that resolved versions are evaluated against 'this PC', and discloses the inspection scope ('reads the .plcproj and folder names only'), which tells the agent the operation is cheap and non-invasive. No mention of ordering/pagination or failure behavior, keeping it short of a 5.

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, front-loaded with the subject ('Library versions (K3)') then the detail, then scope constraints. The parenthetical marker definition is compact and earns its place. Slight density of parentheticals keeps it from a 5, but there is no wasted prose.

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?

A read-only, zero-parameter reporting tool with an output schema on file. The description supplies the only things the structured data cannot: what the returned fields mean (requested vs resolved vs installed) and the '*' convention, so an agent needs nothing further to call it correctly.

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?

The tool takes zero parameters, so the baseline is 4. The description implicitly confirms a no-argument, whole-project sweep ('every library reference of each PLC project'), which is consistent with the empty schema and leaves nothing ambiguous for the agent.

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 ('Library versions... every library reference of each PLC project') and enumerates the three distinct data points it reports: requested version, resolved version, and installed version. The scope note 'Reads the .plcproj and folder names only' cleanly separates it from heavier project-inspection siblings like proj_read_file or proj_scan.

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 by 'Flags a pinned version that is not installed' — an agent can infer this is the tool for diagnosing missing/pinned library mismatches. However, no sibling alternative is named (e.g. proj_references) and there is no explicit when-to-use vs when-not-to-use statement, so context must be inferred.

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