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

Annotations already provide readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context by disclosing that results include install commands and verification status, and that the registry runs an eight-check security audit. This enriches the agent's decision-making beyond the annotations.

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?

Two sentences front-load the action and scope, then concisely add return details and practical selection guidance. There is no filler, repetition of schema fields, or irrelevant information.

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 simple, read-only search with two optional parameters, an output schema, and strong annotations, the description covers the search target, the matching dimensions, result contents, and the security signal to prioritize. Nothing critical is missing for correct selection and invocation.

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%, so the baseline is 3. The description adds value by clarifying the relationship between the two parameters with 'by keyword and/or category', indicating query and category can be used independently or together—something the individual property descriptions do not explicitly state.

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 names a specific verb, resource, and marketplace: 'Search the Sigistry marketplace of Claude Code plugins by keyword and/or category.' It also states what is returned (install command, verification status), which clearly distinguishes plugin search from sibling tools like get_plugin or search_skills.

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 description gives clear context for when to use the tool: when searching marketplace plugins by keyword or category. It does not explicitly name alternatives or exclusion conditions, but the search scope and the added recommendation guidance ('prefer verified plugins') make the intended usage obvious.

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