package_exists

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, covering safety and idempotency. Description adds return format ({exists}) but no further behavioral traits. With annotations present, the description provides some additional context without contradiction.

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 sentences with no fluff: purpose, usage guidance, return type. Front-loaded and efficient. Every sentence earns its place.

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 boolean check tool with clear schema and annotations, description covers all needed aspects: what it does, when to use, what it returns. No gaps given the tool's complexity.

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 description coverage is 0%, yet description offers no explanation of ecosystem or package parameters. The schema itself with enum for ecosystem is clear, but description fails to add any value beyond what schema provides. Missing guidance on how to format or interpret parameters.

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?

Description clearly states 'Boolean registry existence check', specifying verb and resource. It distinguishes from sibling tools like check_bulk, check_compatibility by focusing on simple existence. The use cases (pre-install verification, training data validation) further clarify purpose.

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?

Provides explicit 'USE WHEN' conditions: before install command and when verifying training data. This gives clear context for when to invoke. Does not explicitly mention when not to use or name alternatives, but context is sufficient.

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