Unused installed tools

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered by structured data. The description adds the semantic of "no session ever called" but does not say what counts as a session, over what time window, or where usage data comes from, which matters for interpreting "unused".

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 sentence with no filler, and the key qualifier ("no session ever called") is placed at the end where it sharpens rather than buries the meaning.

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 zero-parameter read-only list tool with no output schema, the definition covers the essentials. The only remaining gap is the imprecise definition of "unused" (all-time vs. a window), which an agent would otherwise have to guess.

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 there is nothing for the description to clarify. The baseline of 4 applies; there are no argument semantics to compensate for.

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 ("List") on a specific resource ("installed MCP servers and skills") with an explicit scope ("that no session ever called"). It is immediately clear what the tool returns; there is no near-identical sibling among the save_/show_/search_ tools to disambiguate against, so it stops short of a 5.

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?

Use is only implied: the description tells you what the output means, so an agent can infer an auditing/cleanup scenario. It offers no explicit when-to-use, when-not-to-use, or alternative (e.g., a companion tool listing all installed tools including used ones).

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