usage

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

Annotations already declare readOnlyHint and destructiveHint=false, so the description isn't obligated to re-state safety — but it adds the useful detail that no permission is required and that the data comes from a local log at ~/.local/state/macos-apps-mcp. Minor redundancy in repeating 'Read-only', but the data provenance is real added 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?

Front-loaded with purpose, then return shape, then the safety/provenance note — a sensible order and only a few lines. Slightly wasteful in that the field-level return breakdown duplicates the output schema.

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 reporting tool this covers purpose, data source, and output contents. Nothing an agent needs in order to call it or interpret the result 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?

Zero parameters, so the baseline is 4 and there is nothing to clarify. The description helpfully frames what selectivity the caller gets (busiest-first ordering, never_used bucket) even though that is technically return data rather than input semantics.

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?

Opens with a specific resource and metric ('Per-tool call frequency') plus the intent behind it ('for pruning rarely/never-used tools'). It's distinctive enough that no sibling is confusable, though it never names the potentially adjacent tools (audit, doctor) to draw the boundary explicitly.

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 pruning use case is stated outright, which effectively tells the agent when to reach for this tool. It stops short of exclusions or naming an alternative for adjacent diagnostics questions.

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