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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds meaningful behavior beyond that: it parses a specific file, returns two pieces of information, and defines the empty case ('reports that none is recorded'), which is exactly the fallback an agent needs.

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?

A single front-loaded sentence that leads with the action and resource before the return behavior. No filler, though the sentence is long and could be split for scannability.

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?

No output schema exists, so the description must carry the return contract, and it does: library used, icons installed, and the none-recorded fallback. Since there are no required parameters and the optional one is fully documented in the schema, little else 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% and the schema already instructs the agent to read the file from disk and omit the field if unreadable. The description adds no syntax or format detail beyond the schema, so the baseline of 3 for fully-documented schemas 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: reads the `.library.json` file and returns the used icon library plus installed icons, or reports none. This is distinguishable from install-icons and find-icon-library. It stops short of explicitly naming how it differs from the sibling find-icon-library, which keeps it at 4.

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?

The phrase 'an earlier icon install left in a project' implies this is a pre-install/pre-check step, giving implied usage. However, it never states when to prefer this over find-icon-library or install-icons, nor any exclusion conditions. Usage is left to inference.

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